Australian Open champion Roger Federer suffered a shock defeat in the Dubai Championships second round by Russian qualifier Evgeny Donskoy.
Federer lost 3-6 7-6 (9-7) 7-6 (7-5) to the world number 116.
Federer had three match points in the second set, served for the match at 5-3 in the third and led the deciding tie-break 5-1 but the Russian fought back brilliantly.
Earlier, Britain's Andy Murray beat Spain's Guillermo Garcia-Lopez 6-2 6-0.
The world number one, 29, is playing his first tournament since his fourth-round defeat at the Australian Open in January.
Murray, who won in one hour and 12 minutes, will face Germany's Philipp Kohlschreiber in the last eight.