Manchester City began their Premier League title defence with defeat away at Tottenham Hotspur on Sunday, knowing that this season's title race could be the tightest in years.
City 's main title rivals all secured resounding opening day wins on Saturday. Manchester United hammered Leeds United 5-1, before Chelsea and Liverpool both won 3-0 against Crystal Palace and Norwich City respectively.
In contrast, City endured a frustrating afternoon in North London, with Son Heung-min scoring the only goal of the game.
The victories for the other title hopefuls, coupled with their own lacklustre display, gave City a stark early warning — too many more slip ups and the others could race ahead.
With games against all three coming up earlyish in the season, there are a few things Pep Guardiola and his staff may have taken note of. The MEN's City fan brands team run through each of the rivals of the lessons learned here:
Manchester United
City's cross-town rivals laid down the gauntlet early on this season — it seems they aren't here to mess around.
Bruno Fernandes scored a hat-trick as United tore through what is undeniably a talented and well-coached Leeds team. They pressed relentlessly from the off and took full advantage of the space left in the channels and behind the Leeds back line.
With four assists on the day, one more than his total for the entirety of last season, Paul Pogba showed the rest of the league and City just how dangerous he can be.
Unshackled from defensive responsibilities thanks to the midfield double pivot of Fred and Scott McTominay, the Frenchman was free to roam the left-hand side and centre of the attacking third.
He showcased his mercurial vision and passing ability by repeatedly splitting open the Leeds defence.
Nobody in white could get near him, so that could be the key when City travel to Old Trafford in November. We could see the likes of Fernandinho or Rodri given the unenviable task of trying to neutralise United's star man. Give Pogba the freedom to dictate play at your peril.
Chelsea
Chelsea's goal-scoring problems look to be a thing of the past.
Chelsea performed well in the bigger games last season, as City know well, but even the appointment of Thomas Tuchel didn't do much to improve their fortunes against sides lower in the league standings.
Timo Werner struggled to find the back of the net all season, with Mason Mount's five goals from open play the most of any player in the squad.
The London club have sought to address that by signing Romelu Lukaku. But even in the Belgian's absence yesterday, they looked much more clinical and lively around the penalty area.
Christian Pulisic in particular impressed, and with Hakim Ziyech currently injured, the American could be a key player when City travel to Stamford Bridge on September 25.
Liverpool
Some have suggested that Liverpool's relative lack of investment in the transfer window could result in them having a down year, but if Saturday's win in Norwich is anything to go by, they look refreshed and ready for a title tilt.
Liverpool fans will be delighted that prize weapons Mohamed Salah and Sadio Mane had a full pre-season to prepare, with neither involved in international competitions over the summer.
Both looked as sharp as ever, with Salah bagging two assists before scoring himself. Even Roberto Firmino and Diogo Jota looked raring to go, despite both playing in the Copa America and Euros respectively.
The return of Virgil van Dijk from long-term injury is of course a huge boost, and while he did look a little of the pace at times, he is sure to form a solid centre-back partnership with new recruit Ibrahima Konate.
The key takeaway for City is not to underestimate Liverpool: with a re-charged attack and van Dijk back to lead the defence, Jurgen Klopp's side will be right up there in the mix.
