| Djokovic, this year's Wimbledon and U.S. Open 
				champion, was able to break Isner three times, and gave credit 
				to his "solid" play for helping him wrap up the match in one 
				hour and 14 minutes.
 "I managed to have three breaks of serve which is sometimes 
				mission impossible," said the top-seeded Djokovic, who missed 
				last year's event due to injury. "I just managed to be at the 
				right place at the right time. I held my serve well and backed 
				it up well from the baseline. From the back of the court I was 
				solid."
 
 Third-seeded Alexander Zverev of Germany shook off a slow start 
				to eventually prevail over fifth-seeded Marin Cilic of Croatia 
				in straight sets, 7-6 (5), 7-6 (1).
 
 Zverev, 21, won 75 percent of his first-serve points against 
				world No. 7 Cilic to clinch the win after two hours and six 
				minutes.
 
 "That first set was key because against Marin you never want to 
				fall behind. He's such a hard-hitting, aggressive player, when 
				he gets confidence it is tough to play against him," Zverev 
				said.
 
 "I wanted to fight back from every score, he was up a break in 
				both sets. I knew it was a very important match, you don't want 
				to start the group stage with a losing record. it was very 
				important to get the win."
 
 Zverev will face Djokovic of Serbia in their second round of 
				round-robin play on Wednesday, while Cilic will take on 
				eighth-seeded Isner.
 
 In doubles action, top seeds Oliver Marach of Austria and Mate 
				Pavic of Croatia recorded a win over No. 8 seeds Frenchmen 
				Pierre-Hugues Herbert and Nicolas Mahut, 6-4, 7-6 (3), in one 
				hour and 47 minutes.
 
 Americans Mike Bryan and Jack Sock also got their campaign off 
				to a winning start Monday. The fifth seeds, who won Wimbledon 
				and U.S. Open titles this year, saved one set point in the 
				second set en route to beating last year's finalists and No. 3 
				seeds Lukasz Kubot of Poland and Marcelo Melo of Brazil, 6-3, 
				7-6 (5), in 87 minutes.
 
 --Field Level Media
 
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