ANDY Murray had to earn his place in the quarter-finals of the Qatar Open after a difficult 7-6 (8/6) 7-5 victory over Gerald Melzer.
The duo shared four breaks of serve in an opening set that was taken to a tie-breaker by the Austrian world number 68 and who fought back from 5-0 down to 6-6 in the first-set decider.
The second set was just as frustrating for the world number one despite him hitting 10 aces and seeing 78 per cent of his first serves in - but he edged past the 26-year-old to set up a meeting against Spain's Nicolas Almagro.
Almagro, the world number 44, sealed his place in the last eight with a 7-6 (7/5) 7-6 (8/6) straight-sets success over Germany's Philipp Kohlschreiber.
World number two Novak Djokovic eased into the next phase with a 6-3 6-4 victory over Argentina's Horacio Zeballos in just one hour and 13 minutes.
Fernando Verdasco defeated fourth seed David Goffin to advance to the quarter-finals in Doha with a 6-1 7-6 (8/6) win over the Belgian, while the evergreen Radek Stepanek was a 6-3 6-2 victor over Arthur De Greef.
Third seed Tomas Berdych won the battle of the Czechs as he triumphed over compatriot Jiri Vesely 7-6 (7/5) 1-6 6-1 in three sets while big-serving Ivo Karlovic defeated Karen Khachanov 7-6 (7/3) 7-6 (7/3).
Britain's Kyle Edmund will face world number four Stan Wawrinka in the quarter-finals of the Brisbane International after both came through their second round matches on Wednesday.
Edmund progressed when opponent Lucas Pouille retired trailing the Briton 6-3 3-1 while second seed Wawrinka beat Viktor Troicki 7-6 (7/5) 6-4.
Third seed Kei Nishikori booked his place in the last eight after coming from a set down to beat qualifier Jared Donaldson 4-6 6-4 6-3.
But eighth seed David Ferrer crashed out of the event following a 4-6 7-5 7-5 defeat at the hands of Australian Jordan Thompson.
In the Aircel Chennai Open, number one seed Marin Cilic fell to a second round defeat to world number 117 Jozef Kovalik by a 7-6 (7/5) 5-7 7-5 scoreline.
Both men earned two breaks apiece during the match but the 24-year-old Slovak used his timely second to his advantage in the decider to serve out one of his biggest victories in his career so far.
Third seed Albert Ramos Vinolas needed just over an hour as he dropped just two games in his comfortable 6-2 6-0 success over Belgium's Steve Darcis.
Israel's Dudi Sela produced a routine 6-2 6-2 win over South Korea's Chung Hyeon while Russian Daniil Medvedev won 6-4 6-3 against Yen-Hsun Lu.
Later at the Qatar Open, fifth seed Jo-Wilfried Tsonga needed just 45 minutes to breeze past Germany's Dustin Brown in a 6-1 6-3 victory and will take on Tomas Berdych for a place in the last four.
