After Kimi Raikkonen won the season opener in Australia, the Finn and his team-mate Romain Grosjean were not a factor at the front in the Malaysian Grand Prix as they finished more than half a minute adrift of race winner Sebastian Vettel.
Boullier reckons that such variations in form were what the team was expecting for the season, especially because of the complications caused by the 2013 Pirelli tyres.
"It is a prediction we had after the winter testing," said Boullier. "It is going to be very, very tight.
"I think you can expect, mainly because of the tyre management situation, a different race winner each time.
"But we can say we are definitely in the top four. Ferrari, McLaren, Red Bull and us are very, very close."
Boullier thinks that the difficulties Raikkonen and Grosjean had in extracting speed from the car in wet conditions - allied to time lost working their way back up the order – were the main factors behind its failure to finish on the podium at Sepang.

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