John Isner reached the semifinals of the Miami Open after easily beating fourth-seeded Kei Nishikori of Japan 6-4, 6-3 on Thursday. The 6-foot-10, hard-serving Isner is the first American man to make the semifinals in Miami since 2011. He'll next meet either world No. 1 Novak Djokovic or David Ferrer on Friday night. Isner won the final eight points of the first set, breaking Nishikori at love to end it. He then ran out to a 3-0 lead in the second set and never faced serious trouble. Big serving John Isner became the first American to reach the semi finals in Miami since 2011 . Kei Nishikori could not cope with Isner's power play in a straight sets 6-4, 6-3 defeat . Nishikori never had a break chance Thursday, and Isner hasn't been broken in the tournament. Meanwhile, Andy Murray will face not one but two of his former team when he meets Tomas Berdych in the other semi final in Key Biscayne. His former fitness coach Jez Green has followed his once close friend and assistant coach Dani Vallverdu, to join the Czech world No 9. Sparks flew when the pair met in this year's Australian Open semi-final, which Murray eventually won in four sets. There will be no love lost when Andy Murray takes on Tomas Berdych in the other semi final . Even mild mannered Kim Sears was captured uttering expletives in the Czech's direction at Australian Open .
John Isner will play either Novak Djokovic or David Ferrer in the last four .
He became the first American to reach Miami Open semi final since 2011 .
Kei Nishikori could not handle Isner's serve in a 6-4, 6-3 defeat .