I've seen where I was up like 5-1 and all of a sudden, for 2 or 3 games, the CPU player play's like a madman, getting to shots he couldn't before, throwing in great serves, and moving like a jack-rabbit. I figure he's just picking up his game, just like in a real match. Usually that burst of energy doesn't last, but sometimes it does. I don't think it's cheating; it's just part of the game. There are times I've been up 5-1 or 5-2 and lost a set, both in TE and real life
Not a good feeling, but hey, stuff happens