Djokovic appeared to be in control, but Del Potro was able to turn the tide somewhat in the second set. The Argentinian was battling some left knee issues -- Del Potro had two separate nasty spills in earlier rounds -- though his mobility hardly seemed affected.
Del Potro pushed Djokovic to a tiebreak in the third set before stumbling. Then, again, the two played to a tiebreak in the fourth set, and, somehow, Del Potro was able to fight off two Djokovic match points and pull even.
The fifth set mostly mirrored the first four, with both men holding serve and trading games. Del Potro stumbled first, and Djokovic was able to take advantage and close out the match.
"It was one of the best matches that I've been a part of. One of the most exciting, definitely," Djokovic said afterwards. "It was so close, you couldn't separate us, except for when I was two sets to one up with a break and I dropped serve. That's why he's a Grand Slam champion. I didn't think I played wrong when I was match points up in the tie-breaker, credit to him for fighting. It was a very high level of tennis."
Both players were noticeably fatigued late in the final set, but Del Potro seemed most affected. And with good reason: At 4 hours, 43 minutes, the match was the longest ever in a Wimbledon semifinal.
"I was ready to play five sets and I managed to play tough and solid at the end," Djokovic said. "I'm just enjoying this victory and I'll think tomorrow about the final. It's probably the most exciting match I've played at Wimbledon, at such a high level. I'm just privileged to be a winner."