Second seed and title favourite completes straight-sets win over American wildcard Ryan Harrison at Flushing Meadows.Rafael Nadal looked quite comfortable in his return to the US Open, beating American Ryan Harrison in straight sets.The second-seeded Spaniard won 6-4, 6-2, 6-2 in the first round Monday.Nadal, the 2010 champion, skipped last year’s US Open because of a left knee injury. He was playing his first Grand Slam match since an opening-round loss at Wimbledon.The 27-year-old Spaniard has captured nine trophies since his return from injury in February, building up a 54-3 record in the process, and he came into New York having won back-to-back Masters titles at Montreal and Cincinnati."It’s a special emotion to be back in New York. It’s a special atmosphere,” said Nadal, who next tackles either Canada’s Vasek Pospisil or Brazilian qualifier Rogerio Dutra Silva."I was nervous before the start, but I hope to have these nerves again in the future if it means I win.”Nadal improved to 16-0 on hard courts this year. The 21-year-old Harrison is 0-20 against top-10 opponents.Both players had 28 winners, but the 97th-ranked Harrison had made 34 unforced errors to 21 for Nadal.The 12-time major champion pounced on Harrison’s second serve, winning 71 percent of the points on it.And with Harrison getting in just 62 per cent of his first serves, Nadal had plenty of chances to break.