After Berger, he became Ayrton Senna's track engineer in the 1993 season, during which the partnership resulted in some of the three-time Brazilian champion's most famous victories.

When Senna was hired by Williams in 1994, Ascanelli left McLaren and returned to Italy in 1995 to work again with Berger and Barnard at Ferrari.

Ascanelli remained in that position until early 1998, when it was announced that he had no plans to travel to that year's races, as his duties had been taken over by Ross Brawn.

In April 2007, Ascanelli returned to F1 with Scuderia Toro Rosso, where he was appointed technical director of the Faenza team.

In mid-2012, his absence from the Grands Prix was the subject of much speculation, until, in September 2012, Toro Rosso confirmed that Ascanelli had left the team.