Playing in a USTA tournament a few years ago. Lost the first set 3-6 and was down 2-5 in the second set and my opponent is serving for the match. He had two match points on his serve and since I was expecting I was going to eventually lose I became more relaxed. I ended up winning the second set 7-5 and then the third set 6-2.
We were one of the last matches of the day and when my opponent was serving for the match I could see the umpire that had been watching our match was expecting his day to be just about over. When we went to a third set I got the sense he wasn't very happy with my opponent for not closing out the match in two sets. Instead of the match being over in about 90 minutes it went on for almost three hours.