Actually, it looks like the Cubs haven't quite clinched yet. An 87-75 tie involving the Cubs, Diamondbacks and Padres or a 4 way tie with them and the Mets would leave the Cubs out. Might be more situations if the Dodgers were also part of it.
A Cubs win or a Diamondbacks loss clinches a spot.
The A's would be eliminated with a loss to the Red Sox.
The Braves would be eliminated with a loss and a Mets win. 84th loss for the Braves, Mets would finish no worse than 79-83.