Pep Guardiola was given a stark reminder of what Harry Kane might have brought to Manchester City but insisted that transfer saga belonged in the past after a shock 3-2 defeat to Tottenham.
City had taken 43 points from a possible 45 across their last 15 Premier League games, while Spurs were on a three-game losing skid heading into Saturday's game at the Etihad Stadium.
Yet a double from Kane, including a winner in the fifth minute of stoppage time, gave the visitors a famous win, completing an improbable double over last season's champions.
City lead the way in the English top flight again this year, but their lead over Liverpool is down to six points, and Jurgen Klopp's team have a game in hand.
Guardiola said City had been involved in a "good game", pointing to Tottenham's deep defending as making his side's task difficult.
He added praise for how Tottenham's front three of Kane, Son Heung-min and Dejan Kulusevski offered a threat to City's backline, adding on Sky Sports: "They are clinical, and the crosses we could not defend."
City wanted Kane during the last close-season, and the feeling was probably mutual, but the England captain remained at Tottenham and has been rejuvenated by Antonio Conte's mid-season arrival.
There is now a genuine title race, and Guardiola said: "I don't need a game today to know it. I knew it a month ago. There's many, many games to play. People are going to drop points."
When asked about Kane in a later news conference, Guardiola said signing the striker "never was an option" for City, despite admitting there was interest, and urged people to "forget" that saga.
He should be so lucky.
"It's not necessary for him to show today the goals he scored to show his quality with the ball. All the UK knows it," Guardiola said, signalling Kane's display came as no surprise.
Spurs boss Conte was impressed his team put their recent rocky form behind them to produce such an eye-catching result.
New recruit Kulusevski scored the opener after slick play involving Kane and Son, and Kane restored Tottenham's lead after an Ilkay Gundogan leveller. Riyad Mahrez looked to have pinched a point with a late penalty, only for Kane to head his second goal of the game.
Conte told Sky Sports: "It was a good win for us and a win we need to try to give us more confidence. it wasn't simple to play against Manchester City after three losses in a row, but this is a process. We are working very hard to try to improve every aspect.
"This type of game has to give us confidence to trust the work we are doing. It was important there was a reaction [to the defeats]."
Conte described Kane as "highly important", adding: "He had chances to score and I think in every game we created the chances to score, and today our strikers did very well and Harry was very good to keep the ball.
"I think the first goal was great because this goal is about our job, our work that we are doing every day."
But Conte warned: "One win is not enough. Don't forget we are coming after three losses, but for sure to win against Manchester City can give you confidence and to trust in what you are doing.
"We can improve a lot. This is a group of players that is fantastic, this group is one of the best groups of players I've worked with in my career. We have a lot of work to do but we are not scared to work."