Racing driver who finished second several times (4)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

MO (short for moment = second) + two S (abbreviation for second), so “second several times”. Mid 20th century Formula 1 racing driver Stirling Moss, perhaps with an extended definition: he won a lot of races but never quite managed to win the Formula 1 World Drivers’ Championship.