The Cheetahs fell to Ifan Phillips’ 78th-minute try for the Ospreys last time out but this time it was they who dished out the late misery, Marais splitting the posts with 10 seconds remaining.
Uzair Cassiem crossed in the third minute but Eoin Griffin added to a double from Matt Healy as the Irish province opened up a nine-point lead with just over 20 minutes left.
A quick response from Rabs Maxwane was converted by Marais, who took his tally for the match to 13 points at the death after Connacht were penalised for collapsing the ruck.
The Cheetahs now hold a 10-point lead over fourth-placed Cardiff Blues in Conference A, with Connacht a further four back, their hopes of reaching the finals dealt a blow.
— Toyota Cheetahs (@CheetahsRugby) March 3, 2018
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