Be the tortoise not the hare
If your determined uncle is the kind of fella who gets narked if someone goes a mile under the speed limit,
use his need for efficiency against him. In your next game, take your time, think about your move and delay, delay, delay! Do your utmost to infuriate your competition and knock them off their game. If they’re still steaming ahead, take a 20-minute toilet break. By the time you’re back, they may well have lost all their oomph!