Andrew Fiffield on how the seeds of resentment may grow to cause real problems for Jose Mourinho.

Jose Mourinho has clearly spent the summer refining his well-developed Midas touch. At the end of arguably his hardest week in charge of Chelsea, the west Londoners have collected six points out of six and edged clear of Arsenal after yesterday's slender victory at Stamford Bridge. If Chelsea really are in the grip of a crisis, maybe they should have them more often.

But nobody is fooled. The champions' two victories have been secured thanks to Hernan Crespo's split second of inspiration against Wigan and Didier Drogba's shin. Their football has been fragmented, unconvincing - a throwback to the stuttering way they started last season.

More worrying for Mourinho, however, is the appearance of a crack in Chelsea's famed camaraderie. The problems began at the JJB Stadium last weekend, when the manager took the almost unprecedented step of publicly lambasting his players for complacency after their undeserved 1-0 win. The Portuguese was not wrong when he called it his team's worst display since he took over as manager.

Then came the highly publicised criticism of Mourinho's squad-rotation policy from his defender Ricardo Carvalho and Arjen Robben, the Dutch winger who lit up the Premiership last year after moving from PSV Eindhoven. As player outbursts go, their comments were tame. Indeed, Robben seemed to be guilty of nothing more than stating the obvious when he suggested, "If you play badly in one match you are immediately on the bench, and that's not good." But at Chelsea, where Mourinho has been rightly praised for fostering a formidable team ethic in football's version of the Harlem Globetrotters, it was big news.

The Portuguese is inexperienced in how to deal with such discontent. As manager of FC Porto, he sucked the best out of a small group of highly talented professionals by convincing them they were the best in Europe. With resources limited, squad rotation was never an issue. Even last season, when Mourinho rarely fielded the same 11 at Chelsea for more than two games at a time, there was barely a murmur of protest.

Amid the euphoria of the Londoners' first title for half a century, their League win and an impressive run to the Champions League semi-finals, such issues were soon forgotten.

But things have changed. Chelsea's players could never have been accused of lacking self-confidence, but now their egos have been swollen by success. It took just one game for Carvalho to complain at being left out of the starting line-up, while Robben is understandably threatened by the arrival of Shaun Wright-Phillips from Manchester City. Even Roman Abramovich does not buy £23 million players to sit on the bench.

Mourinho's spiteful reaction to his players' comments may also have sent a shiver of concern through Stamford Bridge. Having told Carvalho - through the pages of a Portuguese newspaper - he was stupid and needed to see a doctor, he then gave the centre back a humiliating dressingdown in front of his team-mates at their training headquarters last Friday. "I killed him," said Mourinho, flashing his assassin's smile.

His remarks were intended to remind the more militant-minded of Chelsea's squad that dissent will not be tolerated. But Mourinho is playing a dangerous game. The chances are that more players will voice their disappointment at being given bench duty as the season progresses, and the manager cannot afford to fall out with all of them.

It was telling that while Mourinho felt able to publicly crush Carvalho, who had already fallen behind William Gallas and John Terry in the queue for first-team places, Robben's outburst did not prevent him starting against Arsenal. Mourinho may claim that all his players are uniformly precious, yet some are clearly more equal than others.

That in itself could breed resentment. Footballers instinctively protect their own, regardless of their respect for the manager, and Carvalho would have had his team-mates' sympathies in the wake of his rebuke. It would be fascinating to see how Mourinho would react if one of his lynchpins - Frank Lampard, say, or Terry - also publicly questioned his selection policy.

All problems are relative, of course, and Mourinho is unlikely to have lost much sleep last night after his side completed their second victory over Arsenal this season, yesterday's Premiership win coming just two weeks after their 2-1 triumph in the Community Shield.

Even so, Mourinho could learn a lesson from the Gunners manager, Arsene Wenger, and keep his reprimanding in-house. That policy may not please the press pack, which always thrills to the prospect of a public slagging match, but it would preserve the spirit which served Chelsea so well last season.

Otherwise, that crack could turn into a full-scale dressingroom split.

Andrew Fifield is a freelance football journalist based in London. He has written extensively for the Guardian, the Times, the Daily Express and the Sunday Mirror.