Djokovic defeated Del Potro 7-5, 4-6, 7-6, 6-7, 6-3.
The match was the longest men's semifinal in Wimbledon history. Djokovic, the top seed, was playing in his 13th consecutive Grand Slam semifinal. If he wins Wimbledon, it will be his seventh major title.
It took Djokovic five sets on Center Court to defeat No. 8 Del Potro. He had a chance to close out the match in a fourth-set tiebreak, but Del Potro was able to win four points in a row to force a fifth set.
Djokovic earned a 4-3 break up in the fifth set, which enabled him to win the match on his own serve.
The longest match before this was a 1989 match between Boris Becker and Ivan Lendl.
Djokovic will play either No. 2 Andy Murray or No. 23 Jerzy Janowicz in the Sunday final, depending on who prevails in Friday other men's semifinal.