He absolutely did not win games. He was part of the Broncos machine that won games and was dominant in the fourth, similar to how it still is now.
Much has to do with coaching and conditioning, and much else with how that team is built with pass rushing closers, a strong back end which limits late game throwing heroics, and a powerful offensive line which wears down opposing defenses in the first three quarters, and piles it on in the fourth.
The difference, is that this broncos team, with a real QB, is asking the QB to go out and win every time he's on the field, and the games reflect that in the scores and statistics.
Tebow's offense was asked not to lose the game for the first 3.5 quarters of each game, and again, the games reflected that.
I'll give Tebow credit for being part of the teams that won those games late (and also lost three regular season games in a row to close the season, similar to your arch enemy Mark Sanchez), but I won't give him credit for winning those games.