3rd) in the final round in Portugal behind the dominant McLarens of race winner Prost and World Champion Lauda. Early in the 1984 season, Ayrton Senna recorded his only failure to qualify for a Formula One Grand Prix. At round four of the championship, the San Marino Grand Prix at Imola, Toleman decided not to run their cars during Friday qualifying after to a dispute with tyre supplier Pirelli. Senna then suffered a fuel pressure problem in the wet Saturday session which left him stranded on the far side of the circuit between Tosa and Piratella. He was unable to make it back to the pits in time to qualify for the race, his best time of 1:41.585 being 13.068 seconds slower than the time defending World Champion Nelson Piquet had set in his Brabham-BMW to claim pole while being 2.637 seconds slower than 26th and last qualifier Jo Gartner. Tyre supply problems During the off-season, Toleman ran into difficulties over tyre supply and was only able to compete in after Spirit experienced financial collapse, allowing Toleman to take over its Pirelli tyre supply. The roots of this situation lay in Toleman's decision to abandon Pirelli after the 1984 San Marino Grand Prix in response to Michelin and Goodyear's performance advantage. Due to the dispute, Toleman had opted to sit out the first day of qualifying at Imola and this, along with a fuel pressure problem on his Hart powered TG184 in the final session resulted in Ayrton Senna not qualifying for a Grand Prix for the only time in his career. Toleman had already aggravated Goodyear with the same behaviour (that time in favour of Pirelli) in Formula Two, so Michelin was the only alternative. When Michelin subsequently announced its withdrawal from F1 effective at the end of 1984, it left Toleman with bridges to mend. The bridge with Pirelli was not mended in the off-season and as a result, it missed the first three Grands Prix. It was only after the team's new sponsor Benetton purchased Spirit Racing and transferred its Pirelli contract to Toleman did the team return, initially with only one entry. Johansson was to be retained with John Watson driving the second car, but the tyre supply issues prompted Johansson to drive for Tyrrell in Brazil as a replacement for the suspended Stefan Bellof, before replacing René Arnoux at Ferrari from round two in Portugal