To confirm completion of the rally, bears need to push ES back under the June low = 3,655.75:

In contrast, if bulls manage to push ES over 3,718 (66.7% retracement of the preceding decline) that bearish count would become questionable to say the least.
The Bullish alternative count:

Bulls have broken out over 3,718, and the bearish count got severely damaged. Under the Bullish count bulls can push ES at the very least to 3,755 (100% ext of subwave a up). But the rally may extend up to 3,850 or even 3,925. That rally would complete the a up, b down, c up (blue labels) corrective structure and set the stage for another big move down to fresh lows.