Monaco GP, 1985

In the fortnight between the San Marino and Monaco Grands Prix, Toleman finally managed to find tires by buying Spirit's supply of Pirellis. This meant that Spirit dropped out and Toleman was able to field one car. As part of the deal Toleman agreed a three-year sponsorship with Benetton. The team announced that it would run Teo Fabi as Alfa Romeo has refused to release Eddie Cheever to join the operation. Otherwise the field was unchanged.

Pole position again went to Ayrton Senna in the Lotus-Renault with Nigel Mansell second quickest for Williams-Honda. Then came Michele Alboreto (Ferrari), Eddie Cheever (Alfa Romeo), Alain Prost (McLaren-TAG) and Thierry Boutsen in his Arrows-BMW. The top 10 was completed by Keke Rosberg (Williams-Honda), Andrea de Cesaris (Ligier-Renault), Elio de Angelis (Lotus-Renault) and Derek Warwick in the factory Renault.

At the start of the race Senna went away well leading Mansell, Alboreto and Prost, who had overtaken Cheever on the run to the first corner. Further back Gerhard Berger started well in his Arrows-BMW but the engine died almost immediately and he was hit by both Patrick Tambay's Renault and Stefan Johansson's Ferrari. All three were effectively out. At the front Alboreto made quick work of Mansell and the Englishman quickly dropped behind Prost, Cheever, de Angelis and Rosberg. The order then stabilized until lap 14 when Senna suffered an engine failure. Alboreto led for five laps during which time Riccardo Patrese (Alfa Romeo) and Nelson Piquet (Brabham) had a big accident going into Ste Devote. This left oil all over the road and caused Alboreto go go wide and lose the lead to Prost. Lauda went off and stalled. Alboreto had also picked up a slow puncture from wreckage of the road and so had to pit for new tires and dropped behind de Cesaris. he fought back and retook the place and late in the race was able to pass de Angelis as well to take second. But victory was Prost's. Behind Alboreto came de Angelis, de Cesaris, Warwick and and Jacques Laffite (Ligier-Renault).