Two-time world champion Mika Hakkinen says Ferrari can't allow its drivers to fight each other if Sebastian Vettel is to retain a chance of winning the world title this season.

Vettel was outpaced by team mate Kimi Raikkonen in qualifying for the Italian Grand Prix last weekend, the Finn leading from pole on Sunday while Vettel was left to trip over himself while battling an incisive Lewis Hamilton on the opening lap of the race.

For Hakkinen, Ferrari's troubles began after qualifying when the team likely didn't properly plan for race day.

"This was a great performance from Kimi, but a bad result for Sebastian because apparently, the Ferrari contracts give preference to whichever driver is on pole," the Finn said in his post-GP Unibet column.

"If this is true, it was a mistake of leadership and strategy on Ferrari’s part not to sit down with Kimi and Sebastian on Saturday night and plan how to run the race.

"They really did not need to be fighting each other going into the first corner, and when Kimi naturally defended - which he is entitled to do - it put Sebastian off-line."

The end result for the former McLaren driver is that there is no longer any margin for error for the Scuderia.

"There are seven races remaining in this year’s World Championship and Ferrari cannot afford to have further battles between their drivers, mistakes by Sebastian or errors in race strategy," he added.

"To beat Lewis, Valtteri and the Mercedes team, Ferrari now needs to do a perfect job every weekend and hope that Mercedes has some problems."

While Hakkinen underlined Ferrari's mistakes, the former McLaren driver also emphasized the outstanding job done by the Mercedes squad this year.

"No one can say that Lewis is there because the Mercedes has a major advantage," he said.

"He is there because he and the Mercedes team are doing a better job. In my opinion, he is leading the World Championship for three reasons.

"The first has been his natural talent, particularly in the wet, which has meant that he has been able to upset Ferrari’s weekends any time that it has rained.

"The second is that he shows great race craft and does not make mistakes of the kind that Sebastian Vettel has made, especially at race starts. And thirdly he benefits from having a fantastic team partnership with Valtteri Bottas."

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