Georginio Wijnaldum inspired Newcastle to their third win of the season as they beat in-form Liverpool.
The Magpies moved above Sunderland into 18th place in the table after Wijnaldum's shot was deflected off Martin Skrtel's knee, before the Dutchman added a second in injury time.
Liverpool, who had won seven of their last eight games, were poor.
Alberto Moreno was wrongly denied by an offside flag as Reds boss Jurgen Klopp suffered a second defeat in 12 games.
But in a scrappy game which lacked quality, Newcastle achieved a much-needed victory for Steve McClaren, who admitted earlier this week that confidence at the club has been "fragile".
After conceding eight goals in their last two games, the result came courtesy of an improved defensive display from the hosts.
And in Wijnaldum, who took his tally to seven for the season following his £14.5m move from PSV Eindhoven in July, they have a player who has offered the goal-scoring threat they have been previously missing.
Following Liverpool's 6-1 win at Southampton in the Capital One Cup on Wednesday, Klopp's reputation at Liverpool reached new heights.
But his decision to make six alterations, including the omission of Daniel Sturridge and Divock Origi, who scored five goals at St Mary's between them, seemed to backfire.
Winger Jordon Ibe was their best outlet going forward but Christian Benteke was left isolated ahead of him and wasted a good chance from a corner, while Roberto Firmino looked a vastly inferior player to the one who tormented Manchester City two weekends ago.
Once Benteke and Firmino were replaced by Sturridge and Adam Lallana after the hour mark, Liverpool found a better rhythm to their play.
However, Sturridge, playing in only his fifth Premier League game of the season after injury, wasted a good chance to equalise and Moreno was denied a wonderful volley from an angle.
The result leaves Liverpool in seventh place, six points behind fourth-placed Manchester United.
Liverpool did not reach the levels of recent weeks, when they secured away wins at Chelsea and Manchester City, but Newcastle showed a ruggedness and willingness to track back which has been in short supply this season.
Right-back Paul Dummett had a busy afternoon as he came up against the energetic Ibe, but kept the Liverpool youngster at bay, while Vernon Anita and Jack Colback were robust in central midfield.
Elsewhere, forward Siem de Jong, on his first Premier League start of the season, often tracked back to help out his team-mates which helped Newcastle set up a platform for the victory.
Liverpool were more positive once Sturridge was introduced, yet it allowed McClaren's team to sit back and break, which suited the pace of Sissoko and Wijnaldum, and they combined superbly for the second goal, which sent St James' Park into raptures.
Newcastle manager Steve McClaren on the win: "It's absolutely huge, absolutely massive. Once or twice we've taken ourselves to the brink of crisis and clawed our way back and that's what we've done today.
"We worked hard, it is so tough to get a result in this league. We've crawled off the field, we've put in so much effort. That's what we need every week."
Liverpool boss Jurgen Klopp: "I think we deserved a point maybe but not more because we didn't play well enough. I like to play the dirty points too - it's no problem. If Alberto's goal was given it was 1-1 then the game can change. Until then we didn't play as well as we like to.
"I have to watch the game again. We were not really in the game. We were not aggressive enough or close enough. There were good moments for pressing but we didn't do it."
Newcastle travel to Tottenham next Sunday before hosting Aston Villa the following Saturday, while Liverpool are at FC Sion in the Europa League and host West Brom next Sunday.
Full Time Match ends, Newcastle United 2, Liverpool 0.
90:00 +6:48 Full timeFull Time Second Half ends, Newcastle United 2, Liverpool 0.
90:00 +5:26Offside, Liverpool. Dejan Lovren tries a through ball, but Divock Origi is caught offside.
90:00 +2:56 Goal scoredGoal! Goal! Newcastle United 2, Liverpool 0. Georginio Wijnaldum (Newcastle United) right footed shot from the centre of the box to the bottom right corner. Assisted by Moussa Sissoko with a through ball.
90:00 +1:18Delay over. They are ready to continue.
90:00 +0:18Delay in match Martin Skrtel (Liverpool) because of an injury.
88:31Attempt saved. Dejan Lovren (Liverpool) header from the centre of the box is saved in the bottom right corner. Assisted by Alberto Moreno with a cross.
88:07Corner, Liverpool. Conceded by Moussa Sissoko.
85:16Attempt missed. Dejan Lovren (Liverpool) header from very close range misses to the left. Assisted by James Milner with a cross following a corner.
84:59Corner, Liverpool. Conceded by Vurnon Anita.
82:58Foul by Divock Origi (Liverpool).
82:58Paul Dummett (Newcastle United) wins a free kick in the defensive half.
81:53Offside, Newcastle United. Florian Thauvin tries a through ball, but Ayoze Pérez is caught offside.
81:17 SubstitutionSubstitution Substitution, Newcastle United. Florian Thauvin replaces Papiss Demba Cissé.
78:38Offside, Liverpool. James Milner tries a through ball, but Alberto Moreno is caught offside.
76:33 SubstitutionSubstitution Substitution, Newcastle United. Yoan Gouffran replaces Jack Colback.
74:33Attempt missed. Daniel Sturridge (Liverpool) right footed shot from the right side of the box misses to the left. Assisted by Adam Lallana with a through ball.
74:05 SubstitutionSubstitution Substitution, Liverpool. Divock Origi replaces Jordon Ibe.
73:42Attempt missed. Daniel Sturridge (Liverpool) left footed shot from outside the box misses to the right. Assisted by Jordon Ibe.
68:27 Goal scoredGoal! Own Goal by Martin Skrtel, Liverpool. Newcastle United 1, Liverpool 0.
Attempt missed. Georginio Wijnaldum (Newcastle United) right footed shot from the right side of the box misses to the left. Assisted by Moussa Sissoko with a cross.
67:11 SubstitutionSubstitution Substitution, Newcastle United. Ayoze Pérez replaces Siem de Jong.
66:33Adam Lallana (Liverpool) wins a free kick in the attacking half.
66:33Foul by Jack Colback (Newcastle United).
62:19 BookingBooking Papiss Demba Cissé (Newcastle United) is shown the yellow card for a bad foul.
62:05Adam Lallana (Liverpool) wins a free kick in the defensive half.
62:05Foul by Papiss Demba Cissé (Newcastle United).
61:45 SubstitutionSubstitution Substitution, Liverpool. Daniel Sturridge replaces Roberto Firmino.
61:31 SubstitutionSubstitution Substitution, Liverpool. Adam Lallana replaces Christian Benteke.
59:30 BookingBooking Vurnon Anita (Newcastle United) is shown the yellow card for a bad foul.
59:25Joe Allen (Liverpool) wins a free kick on the left wing.
59:25Foul by Vurnon Anita (Newcastle United).
57:05Foul by Joe Allen (Liverpool).
57:05Georginio Wijnaldum (Newcastle United) wins a free kick in the defensive half.
54:05Corner, Newcastle United. Conceded by Martin Skrtel.
54:02Attempt blocked. Georginio Wijnaldum (Newcastle United) right footed shot from outside the box is blocked. Assisted by Jack Colback.
52:01Attempt missed. Joe Allen (Liverpool) right footed shot from outside the box misses to the left. Assisted by Roberto Firmino.
50:32Attempt missed. Georginio Wijnaldum (Newcastle United) right footed shot from the centre of the box is close, but misses to the right. Assisted by Moussa Sissoko.
48:54Foul by Dejan Lovren (Liverpool).
48:54Papiss Demba Cissé (Newcastle United) wins a free kick in the defensive half.
47:14Foul by Roberto Firmino (Liverpool).
47:14Jack Colback (Newcastle United) wins a free kick in the defensive half.
45:43Attempt missed. Roberto Firmino (Liverpool) right footed shot from the left side of the box misses to the left. Assisted by James Milner.
45:00Second Half begins Newcastle United 0, Liverpool 0.
45:00 +1:15 Half timeHalf Time First Half ends, Newcastle United 0, Liverpool 0.
45:00 +0:42Attempt missed. Jordon Ibe (Liverpool) right footed shot from outside the box is just a bit too high. Assisted by Christian Benteke.
44:52Attempt missed. Georginio Wijnaldum (Newcastle United) right footed shot from outside the box is too high from a direct free kick.
44:03 BookingBooking Lucas Leiva (Liverpool) is shown the yellow card for a bad foul.
43:57Foul by Lucas Leiva (Liverpool).
43:57Siem de Jong (Newcastle United) wins a free kick in the attacking half.
43:10Attempt missed. Chancel Mbemba (Newcastle United) header from the centre of the box is too high. Assisted by Papiss Demba Cissé following a corner.
42:41Corner, Newcastle United. Conceded by Jordon Ibe.
41:46Foul by Alberto Moreno (Liverpool).
41:46Jack Colback (Newcastle United) wins a free kick in the defensive half.
37:26Foul by James Milner (Liverpool).
37:26Georginio Wijnaldum (Newcastle United) wins a free kick in the defensive half.
34:12Foul by James Milner (Liverpool).
34:12Vurnon Anita (Newcastle United) wins a free kick in the defensive half.
33:01 BookingBooking Jack Colback (Newcastle United) is shown the yellow card for a bad foul.
32:58Roberto Firmino (Liverpool) wins a free kick in the defensive half.
32:58Foul by Jack Colback (Newcastle United).
32:31Joe Allen (Liverpool) wins a free kick on the right wing.
32:31Foul by Vurnon Anita (Newcastle United).
31:13Nathaniel Clyne (Liverpool) wins a free kick in the defensive half.
31:13Foul by Papiss Demba Cissé (Newcastle United).
30:01Attempt blocked. Nathaniel Clyne (Liverpool) right footed shot from outside the box is blocked. Assisted by Christian Benteke.
26:12Corner, Liverpool. Conceded by Paul Dummett.
20:45Attempt missed. Christian Benteke (Liverpool) right footed shot from very close range is high and wide to the left. Assisted by Joe Allen with a headed pass following a corner.
20:08Corner, Liverpool. Conceded by Paul Dummett.
18:44Foul by James Milner (Liverpool).
18:44Jack Colback (Newcastle United) wins a free kick in the defensive half.
1:40Foul by Christian Benteke (Liverpool).
1:40Chancel Mbemba (Newcastle United) wins a free kick in the defensive half.
1:09Corner, Liverpool. Conceded by Jack Colback.
1:07Attempt blocked. Martin Skrtel (Liverpool) right footed shot from outside the box is blocked.
0:40Corner, Liverpool. Conceded by Jack Colback.
0:14Corner, Liverpool. Conceded by Fabricio Coloccini.
0:00First Half begins.
0:00Lineups are announced and players are warming up.
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