The blue and papaya orange MCL34 car was unveiled by 34 team employees at the former champions' Woking headquarters before Sainz and 19-year-old British rookie team mate Lando Norris stepped up to admire it.
Sauber will not appeal against their exclusion from Sunday's Australian Grand Prix after an internal investigation showed they had made a mistake, the Formula One team said on Tuesday.
Force India plan to give their 2009 Formula One car its track debut in early March after working flat out to integrate the new Mercedes engine and McLaren gearbox.
A summary of sports events and persons who made news on Thursday