Grievous fought Mundi and co when they were exhausted, ambushed and unnerved. Against a team like this that's battle-ready to take him on he has no chance. This team is also quite a bit stronger in the Force than the previous team.
They weren't completely exhausted, and he didn't stealth kill any of the main ones he fought, but yeah they were tired and unnerved somewhat. Although this version of Grievous has other feats like defeating Durge and Ventress "handily", dueling evenly with Windu, killing several companies of Clone troopers with his bare hands with minimal training ect. A company contains something like 124 clones. I think it can go away for sabers and he'd probably lose the all out round.
__________________ “The galaxy must experience the pain of death and the rapture of rebirth as I have. I will bring chaos. It is time for war.”