On his 15th attempt, Marin Cilic has beaten Novak Djokovic. The Croatian hit past the World No. 1 with power tennis on Friday at the BNP Paribas Masters in Paris, upsetting the top seed 6-4, 7-6(2) in one hour and 45 minutes. Cilic, who qualified for the Barclays ATP World Tour Finals on Thursday, will meet American John Isner in Saturday's semi-final. “It was really, really good, really good today, and just can't be happier about that,” Cilic said. “Just another sign that I'm in a really good form and produced some great tennis today.” Djokovic's loss means that Andy Murray now controls his fate in the battle for No. 1. The Scot will become No. 1 in the Emirates ATP Rankings if he reaches the Paris final. Murray beat Tomas Berdych 7-6(9), 7-5 in the Paris quarter-finals on Friday. Cilic finally prevailed against Djokovic by attacking him from all over the court. The 6'6” right-hander struck nine aces and went 10/13 when approaching the net. At 1-0, 0/30 on Djokovic's serve in the second set, Cilic had won 15 of the past 19 points. And when Cilic let up, Djokovic struggled to wrestle away control. The Serbian broke Cilic for the first time at 4-all in the second set and had a chance to serve for the set. But Djokovic double faulted twice to hand the break back to Cilic. “He definitely played better today, and he deserved to win... I wasn't on the level that I could have been on,” Djokovic said. “I was also... in a good position to take the match into the third set, and then two double faults. Just in important moments I wasn't able to deliver.” Before Friday, Cilic had lost the past 12 sets he'd played against Djokovic, a stretch that dated back to 2014 Wimbledon. Now Cilic is a match away from his second ATP World Tour Masters 1000 final of the season (Cincinnati, d. Murray). “I felt on the court really, really good, and it's a great time for me. As I was mentioning these last few days, the end of the season is just getting better and better,” said Cilic, who won the Swiss Indoors Basel title last week (d. Nishikori). “Producing great tennis today is great, but still I want to do it tomorrow and the day after and continue to play well.” Earlier on Friday, Isner pulled away from compatriot Jack Sock to reach his first ATP World Tour Masters 1000 semi-final of the season. The 6'10” American struck 17 aces and broke Sock three times to win 7-6(6), 4-6, 6-4 and reach the semi-finals at a Masters 1000 tournament for the first time since April 2015, during the Miami Open presented by Itau. “Very tough match. Certainly could have gone either way. I thought I played very well. I'm happy to move on," Isner said. He will try to continue his late-season turnaround against Cilic on Saturday. The North Carolina native has not won an ATP World Tour title yet this season, marking the first time since 2009 that he's gone this deep into a year without a championship. After reaching the third round of the US Open, Isner lost his openers at the Shanghai Rolex Masters (l. to A. Zverev) and the If Stockholm Open (l. to del Potro). But last week, he reached the quarter-finals in Vienna before falling to eventual champion Andy Murray. “Up to this point I have been very disappointed with how I have played this year,” Isner said. “But I think I have turned a corner. I have a very good team on my side. I am relaxed, but I also know going into this event I have played well here before quite a lot of times. I made the quarter-finals last year and made the semi-finals [in 2011].” Isner had to rally in the start of the third to get past Sock. The 24-year-old Sock had all the momentum after breaking Isner for the first time all tournament at 3-4 and again at 5-4 to even the match. But Isner pounced in the third set, breaking Sock twice and sprinting to a 4-0 lead. Isner is now 52/55 on serve in Paris. “I was fortunate to start off very well in the third set, put that second set behind me,” Isner said.