MIAMI (AFP) - Once-invincible Roger Federer was reduced to a rare bout of racket-bashing Friday as he was toppled in the semi-finals of the Miami ATP Masters 1000 by Serbian Novak Djokovic. Djokovic, ranked number three in the world, defied the blustery conditions to beat the world number two 3-6, 6-2, 6-3 in one hour and 46 minutes. The Serbian, who triumphed here in 2007, will face world number four Andy Murray of Britain in Sunday's final. Murray became the first British finalist at the event with a 6-1, 5-7, 6-2 victory over sixth-seeded Argentinian Juan Martin del Potro. Del Potro had shocked world number one Rafael Nadal in the quarter-finals. Federer, the 13-time Grand Slam champion, who is in search of his first title of 2009, comfortably won the first set as Djokovic found his feet, but could find no answers after that - finishing with 35 unforced errors. "Novak played bad at the beginning, and I finished worse than him," said Federer, who lost seven straight games bridging the second and third sets. That span included four breaks of Federer's serve, after he had had surrendered his serve just once in the tournament and contributed to a rare glimpse of temper from the normally restrained Swiss, who broke a racquet after yet another forehand miss in the third game of the final set. "I was just frustrated," Federer said. "Didn't feel great. It's just a natural thing I did." While Federer struggled in virtually every aspect of his game, his forehand was his biggest liability. Djokovic said he tried to exploit Federer's difficulties. "I tried to change pace and play fast, and then play a bit slower with more spin," Djokovic said. "He usually expects a ball on the backhand side, because that's where the players try to play him. But I'm not giving him any consistency on one side so he can really be comfortable." "You try hard and then it's just not working," Federer said. "Today it is different just because there's so much wind as well. Once you start feeling bad, it's kind of tough to regroup." Djokovic said the windy weather and some early nerves both played a role in his shaky start. "Even though I served really well I was quite nervous and making lots of unforced errors," he said of the first set. "But then it changed. I was just playing smarter afterwards... We kind of changed roles." Djokovic said that even when Federer lost his cool, he tried not to get distracted. "Look, it's obvious frustration," Djokovic said. "I just tried to keep my focus. I was on a roll in this period of the match, so I just tried to continue on playing patiently and win the match." Murray, 21, booked his second straight final in a Masters 1000 event, having fallen to Nadal in a wind-whipped championship match at Indian Wells. While del Potro got off to a slow start in the wake of his physically demanding victory over Nadal on Thursday, Murray was unable to put him away in the second set, dropping his serve at love to in the 12th game to lose the set. Trailing 2-4 in the third set, del Potro called for a trainer for treatment of cramps, but Murray kept his concentration and took the game on his fourth break point and went on to serve out the match.