Manchester City cruised to a victory that keeps them seven points behind their city rivals, who won 4-0 at Wigan, but they were left counting the possible cost of an injury suffered by Sergio Agüero.
Stoke City turned up and did little else but this was hardly a surprise. This was their 10th defeat in 10 league matches in Manchester since they were promoted to the Premier League in 2008.
For City the afternoon's sole sour note was Agüero's hamstring injury that forced him off shortly after he scored his 73rd-minute penalty. The strain rules him out of Watford's visit on Saturday in the FA Cup and possibly the match against Arsenal at the Emirates on Sunday week. The latter is obviously the more important, possibly even pivotal given that United play Liverpool on the same day.
"It's the hamstring, 100%," said the manager, Roberto Mancini. "I don't think it will be serious but the next game in the FA Cup maybe he can't play."
The Italian's assistant, David Platt, was more gloomy, saying: "It's difficult to assess an injury like that for how long it's going to be. He'll be doubtful for Arsenal." Mancini, though, remained upbeat, and was particularly cheered that his side had scored seven times in their past two games.
"It was a good performance," he said. "We are happy for this reason, we scored three goals against the best defence in the Premier League. It is always important to score goals when you have the chance because we should remember very well that we won the championship last year on goal difference. It's important not to concede a goal. Last year I don't know how many clean sheets we had – this is important as maybe we can score in all the games. Now I think we start to score and this is important."
City dominated the first half even if they were far from their best but took a deserved lead only as it drew to a close through Pablo Zabaleta. While the home fans hissed at Stoke for slowing the game down when taking a throw-in or goal-kick, they endured ample frustration from their own team.
Before Zabaleta's 43rd-minute opener Agüero came closest to scoring but, as has been the pattern this season, City lacked a cutting edge.
After the half-hour a Gareth Barry cross from the left, following industrious work from the impressive James Milner, was headed against Asmir Begovic's right post. The Argentina forward, partnering Edin Dzeko instead of Carlos Tevez, had previously created the game's best chance after 22 minutes when he left Ryan Shawcross trailing before unleashing a 25-yard shot that Begovic saved.
Dzeko, the scorer of two in the weekend's 4-3 win at Norwich City, had Mancini hopping with annoyance at two clumsy contributions before half-time. First he smacked the ball straight out of play when attempting to work an opening down the right, then wasted a Milner pass by blasting his shot over the bar.
Ten minutes into the second half Dzeko redeemed himself. City won a free-kick down their right which Yaya Touré slotted behind a slothful Glen Whelan to Agüero. When the striker's cross-shot was palmed out by Begovic his partner Dzeko was on hand to score his ninth league goal of the season. To celebrate the Bosnian lifted his City shirt to reveal a T-shirt bearing a happy new year greeting but there was scant bank holiday cheer from the referee, Michael Oliver, who booked him for the gesture.
Oliver then messed up his own lines when he awarded City's penalty, having failed to spot that Steven N'Zonzi's trip on David Silva came outside the area. Agüero could not have cared less as he stepped up to make it 3-0 with his eighth league goal in 14 starts.
There was time for Whelan to force Joe Hart into pushing a 30-yard humdinger on to his left post on 86 minutes but it served chiefly to emphasise that the visitors had barely threatened before then.
Tony Pulis's assessment was honest. "I've got no complaints," the Stoke manager said. "They were the better team. Someone has just asked me what the difference was and I said about £220m. For us to come here and get anything we have to bring our A game and City have to be off it, and that wasn't the case today. But sometimes you have to look at the reality of everything and they have got a bit of a head start on clubs like us."
City must now work out how to cope without Yaya Touré for potentially the rest of the month and the first week of February should Ivory Coast make the final of the Africa Cup of Nations. "It's irrelevant whether Yaya disappears or not. The challenge is to keep winning football matches," said Platt.
The absence of Kolo Touré, who will fly out to South Africa with his brother to join up with their national squad for the tournament, should offer Joleon Lescott, who started here for the first time in the league since 1 December, more chances to re-establish himself.