Manchester City opened up a three-point lead at the top of the Premier League with a game in hand to come as Pep Guardiola's men beat Sheffield United 1-0, while Manchester United played out a goalless draw at Arsenal on Saturday.
Gabriel Jesus scored the only goal inside the first 10 minutes at the Etihad as City extended their winning run to 12 games in all competitions.
Ferran Torres and Jesus were two of five changes made by Guardiola and they combined to make the breakthrough as the Brazilian tapped home for his first Premier League goal since November.
City failed to build on the lead, but comfortably held out for a 15th clean sheet in their last 19 games.
"People think if we won the last one 5-0, we will win this one 5-0. This is the real world, not a fairytale," said City manager Pep Guardiola.
"Today when I see Sheffield is bottom of the league. You see his team and realise how tough is the Premier League."
Second-placed United could have moved back within one point of their local rivals, but for the second time in four days, after suffering a shock defeat by Sheffield United on Wednesday, their title challenge faltered.
Edinson Cavani wasted a golden opportunity for United when the striker volleyed wide in the closing moments, while Alexandre Lacazette's free-kick for Arsenal came back off the bar.
"The Sheffield United result of course was disappointing when you're at home. If you feel, away at Arsenal, you deserve a win that's a step forward," Solskjaer said.
Arsenal are undefeated in their last seven league matches and edged to within six points adrift of the top four despite missing Pierre-Emerick Aubameyang, Bukayo Saka and Kieran Tierney.
Aston Villa moved above the Gunners into eighth after Ross Barkley's header earned a 1-0 win at Southampton.
Dean Smith's men had goalkeeper Emiliano Martinez to thank for brilliant saves to deny Che Adams and Jan Bednarek, while Danny Ings had a goal ruled out for offside deep into stoppage time as Southampton slumped to a third straight league defeat.
- Newcastle ease pressure on Bruce -
At the other end of the table, Newcastle pulled clear of the drop zone with a first win in 12 games, beating Everton 2-0, while relegation rivals West Brom and Fulham played out a 2-2 draw.
Magpies manager Steve Bruce's future was under the spotlight after a wretched run that plunged his side into the relegation dogfight.
But Callum Wilson scored twice in the final 17 minutes to earn a deserved victory.
Everton were punished for a poor performance when Wilson header home from a corner and then sealed the win on the counter-attack in stoppage time.
"There's no disputing it -- it's been very difficult," said Bruce.
"We're trying to be more on the front foot and push up the pitch. We were a lot better."
Bruce's men are now eight points clear of the relegation zone after a point each did little for West Brom or Fulham's battle to beat the drop.
The visitors were dominant in the first half at the Hawthorns and were made to regret not building on Bobby Decordova-Reid's opener.
Kyle Bartley levelled for the Baggies two minutes into the second half before new signing Mbaye Diagne teed up Matheus Pereira to turn the game around.
Ivan Cavaleiro's equaliser ensured Fulham remain above West Brom in 18th and edged to within four points of safety.
Crystal Palace eased fears they could be dragged into a scrap for survival as Eberechi Eze's winner earned the Eagles a 1-0 win over Wolves to move up to 13th.