Two-time defending champion Novak Djokovic suffered a shock defeat at the hands of Tommy Haas to leave Andy Murray in the box seat at the Sony Open in Miami.
Veteran German Haas completely outplayed the world number one for a 6-2 6-4 victory meaning Murray, who earlier beat Andreas Seppi by the same scoreline, is the highest seed left in the tournament going into the quarter-finals.
From 2-1 down in the first set, Haas won seven straight games to got 6-2 2-0 up and, though Djokovic eventually broke back to level, the 34-year-old held on for his first victory against a world number one since 1999.
Haas held his first two service games to love and then sealed the first break of the match as Djokovic netted, and the Serbian handed him another with a poor shot at net. The 15th seed took the first set in less than half an hour, then kept on rolling with a break to open the second, in part thanks to a double fault from his opponent.
Djokovic saved more break points before holding then pounced on some rare unforced errors from Haas to seal a break of his own and level at 3-3. Haas broke again, though, at 4-4 and it proved decisive as he sealed the match with a forehand winner. Haas' prize is a last-eight meeting with 11th seed Gilles Simon, who beat Janko Tipsarevic in three sets.
Murray breezed into the quarter-finals, where he will face Marin Cilic, after cruising past 16th seed Seppi. Murray has yet to drop a set in this tournament and this did not seem likely to change as he was rarely tested by his Italian opponent, whose sole break point opportunity came in the final game.
"It was swirling a little bit at the start and he made more unforced errors than he usually does," Murray told the Independent. "I was able to track down a lot of his balls because he wasn't timing his shots that well. But he started going for his shots more in the second set and made it tough for me."
A limp forehand into the net immediately gave Murray two break points in the opening game and another unforced error from Seppi gave the world number three the initiative. Seppi won just four points on Murray's serve in the first set and was broken again in the seventh game as the US Open champion put one foot into the next round.
The second seed wasted three break point opportunities at the start of the next set. Murray then found himself 4-3 and 0-30 down on his serve before storming back to level. In the very next game, Murray earned his fourth break point opportunity of the set and he would not be denied this time as Seppi crashed a forehand into the net.
The Scot booked a meeting with ninth seed Cilic who beat Jo-Wilfried Tsonga 7-5 7-6 (7/4). There were also wins for the third and fourth seeds, David Ferrer and Tomas Berdych, as well as Richard Gasquet and Jurgen Melzer.