blue, that's not true. Cubs would clinch at least a tie with any 7 wins and an outright with 8 wins. The reason is that the Giants and Dodgers cannot win every day -- they play each other 6 more times! And the Cubs need only beat the LOSER between them. So ideally for the Cubs, one of those teams would hammer the other out of contention. Astros 3 losses behind so if they went 9-0 Cubs would need 7-3 to tie.
6-4 will probably get it done for the Cubs.