Matt Ritchie condemned Manchester United to a shock 1-0 defeat at struggling Newcastle, while Liverpool cemented their top four place with a 2-0 win over Southampton on Sunday.
United's second defeat in their last three Premier League games leaves them 16 points behind leaders Manchester City.
Jose Mourinho's second placed side, beaten by Tottenham in their last away game, were rarely at their best at St James' Park and paid the price in the 65th minute.
United defender Chris Smalling was booked for needlessly diving inside his own half and from the resulting Jonjo Shelvey free-kick, Dwight Gayle latched onto a header and played a backheel towards Ritchie.
His run was completely untracked by United's sloppy defence and the Newcastle winger fired low past David De Gea.
Mourinho responded by pulling off Paul Pogba after another underwhelming display from the France midfielder.
And United should have equalised soon after, but when Newcastle failed to clear a corner, Anthony Martial saw two shots blocked on the line by Gayle.
"Newcastle fought like animals, I hope they take that as a compliment. The gods of football were on their side," Mourinho said.
"It wasn't going to happen for us today. Newcastle gave what they have, that's a beautiful thing in football.
"We made a defensive mistake and when they are in front they had only one thing in mind and gave their lives to keep a clean sheet."
Newcastle had kicked off in the relegation zone, but a first win in five league games -- their first success against United since 2013 -- lifts them to 13th place.
At St Mary's, Liverpool moved above Tottenham into third place as goals from Roberto Firmino and Mohamed Salah killed off lowly Southampton.
Jurgen Klopp's side, who featured former defender Virgil van Dijk on his first return to the club he left in January, took a sixth minute lead when Brazil forward Firmino netted for the 20th time this season.
- Dream season for Salah -
Saints defender Wesley Hoedt made a hash of dealing with Alex Oxlade-Chamberlain's pass, allowing Salah to tee up Firmino for a clinical finish.
Liverpool increased their lead in the 42nd minute when Firmino turned provider for Salah with a fine flicked pass that the Egypt forward slotted home for his 29th club goal of a dream first season with the Reds.
Klopp's men are four points clear of fifth placed Chelsea, who face West Bromwich Albion on Monday, as the battle hots up to qualify for the Champions League via a top four finish.
"It was not a brilliant performance. It was difficult circumstances with the wind. We did the job. That is very important," Klopp said.
"We scored early, got the second goal in the right moment and then controlled the game.
"We want to finish the season top four and we need the points."
Southampton are third bottom following their first defeat in five league matches.
Huddersfield climbed out of the relegation zone after a 4-1 win against Bournemouth at the John Smith's Stadium.
David Wagner's team took a seventh-minute lead as Alex Pritchard collected Steve Mounie's pass and drilled in his first Huddersfield goal since his January move from Norwich.
Junior Stanislas equalised for Bournemouth with a cool finish from Ryan Fraser's cross seven minutes later.
But Benin striker Mounie restored Huddersfield's advantage with a 27th-minute header and Steve Cook's own goal put the hosts in control in the 66th minute.
Rajiv van La Parra converted a stoppage-time penalty to lift Huddersfield out of the drop zone.
Huddersfield's first league win in nine matches was marred by an injury to Australia midfielder Aaron Mooy, who was stretchered off with a knee problem 15 minutes from time.