About 3 hours 20 mins, USTA match a couple years ago. I won 7-6 5-7 10-7 (match tb). I was playing a friend that I knew was very closely matched with me. We started playing at 9:00, and every game was close with many deuces and several multiple deuces. At 5-5, I left the court to go out and chase a ball that we hit over the fence. A couple matches were done and one guy asked if we split sets. I pulled out that set with a 10-8 tb. It was after 10:30 already at this point.
The second set was a little quicker, but not much (and just as close). I got a match point with him serving at 4-5 30-40 and netted an easy passing shot. This turned the momentum back towards him. We split around 11:55.
We contemplated a match tb, but decided to play out the thrid. As we started, the local high school tournament started coming on the courts around us. At 2-2 in the third, at about 12:10, the tournament director came out and told us we had to get off the courts for the tournament and that we were over an hour past our time. We told him this was an untimed USTA match and that we were in the thrid set. He let us go back to playing, but at this point, we decided it was probably best to abondon the 3rd and play a match tb instead to let the tournament use the courts (this was the HS state tournament, so it was important). There were 2 or 3 guys from our teams still hanging around watching at the end. They said that was the best match they'd seen all season.
I played the same guy again the next time we played that team and won again 6-7 7-6 10-6, although we kept that one around 2:15-2:30 on the clock. I guess you could say we're fairly evenly matched. LOL.