Ferrari has blamed a wheelnut for the lengthy pit stop which cost Sebastian Vettel a certain podium.

With Kimi Raikkonen out barely before the race had begun, the Maranello outfit's hopes rested on the shoulders of Sebastian Vettel.

Whilst the Ferrari still didn't have the pace to challenge the Mercedes duo, Vettel appeared to be heading towards his sixth podium finish of the year.

However, at his pit stop the German was delayed when his crew encountered a problem with the wheelnut on his right-rear. Rejoining the race behind Massa, despite strong pace, and using almost every trick in the book, he was unable to overtake the Brazilian who went on to score his best result of the year.

"We had the problem with the wheelnut and it's not the first time," team boss Maurizio Arrivabene told reporters, "we have to make sure that it does not happen again.

"It was not a problem of the mechanics," he continued, "it was our problem and we have to make sure we fix it.

"Sebastian made a very good race but we threw away the podium one more time for a stupid piece that needs to be fixed as soon as possible. For me it is not acceptable."