 Complete the following phrase:  Jackie Stewart had raced for Tyrrells Formula 2 Matra team and signed to race for them in Formula 1 for 1968, having spent two fruitless years with BRM. However at the first event in 1968, the South African Grand Prix, he raced the interim MS9, but after qualifying an impressive third, he retired due to engine failure. Stewart then injured his wrist in a F2 race at Jarama, so at the Spanish Grand Prix Jean-Pierre Beltoise debuted the car instead, setting the fastest lap and finishing in fifth place. Beltoise then switched to the works MS11 and Johnny Servoz-Gavin raced the car at the 