Manchester United scored twice inside four minutes to stun Manchester City, securing a 2-1 derby win at Old Trafford that took the Red Devils a point behind the champions in the table.
City looked in control after Jack Grealish had come off the bench to good effect for the second Premier League match in a row, heading in from Kevin De Bruyne's cross on the hour, three minutes after being introduced.
United levelled on 78 minutes when Marcus Rashford was put through but, knowing he was offside, elected to leave the ball for Bruno Fernandes to finish.
Soon after, Rashford put the hosts ahead, scoring for the seventh match in a row in all competitions by converting Alejandro Garnacho's cross.
United remain third on 38 points, a place and a point behind City, who suffered a third defeat of the season.
A first senior brace from Solly March inspired Brighton & Hove Albion to a 3-0 win over Liverpool that sent them above the Reds in the table. March struck twice inside seven minutes early in the second half, while substitute Danny Welbeck added gloss to the scoreline late on.
A fifth win in seven matches sends Brighton seventh, on 30 points. Back-to-back defeats put Liverpool two points and two places behind.
Saturday's results have tightened things at the bottom of the table, where only two points separate the teams from 14th down to 20th.
A brace from James Ward-Prowse gave Southampton a first league win under Nathan Jones as they came from behind to beat Everton 2-1, earning a first win at Goodison Park for almost 26 years.
Everton's directors did not attend the match, having been advised it was best for their own safety in light of planned protests by home fans.
The mood at Goodison was initially lifted when Amadou Onana headed Everton in front. But Ward-Prowse struck twice after the break. The second was his 16th direct free-kick goal in the competition, putting him two behind David Beckham's record.
Southampton remain bottom but now have 15 points, the same as Everton, who have collected only two points from their last seven matches and drop to 19th.
Nottingham Forest are up to 13th thanks to a 2-0 home win over Leicester City. Both goals came through Morgan Gibbs-White assisting Brennan Johnson in the second half, giving Forest back-to-back league wins for the first time this season and 20 points.
Leicester are without a point since the return of the competition after the World Cup and drop to 15th with 17 points.
Wolverhampton Wanderers' revival under Julen Lopetegui continued as they climbed out of the relegation zone with a 1-0 win over West Ham United.
Daniel Podence scored the decisive goal, his third in four matches, that sent Wolves up to 16th, with 17 points. West Ham, with just one point in their last seven, fall to 18th on 15 points.
Brentford are up to eighth thanks to a 2-0 win over AFC Bournemouth. Ivan Toney's fourth penalty of the season, and 13th goal in total, put them ahead in the first half and Mathias Jensen sealed a win that makes it seven without defeat for the Bees, their best run in the competition.
An eighth defeat in nine league matches, with no goals scored in the last four, mean AFC Bournemouth are a place and a point above the bottom three, on 16 points.
The defeat for Man City offers Arsenal the chance to open up an eight-point lead, but they must secure a first league win at Tottenham Hotspur in nine attempts to do so.
Newcastle United will also look to exploit City's defeat to go level with them and return to third by beating in-form Fulham at St James' Park.
Chelsea will eye a second league win in nine when they host Crystal Palace, who have lost three of their last four.