NEW YORK —  Andy Murray got off to an easy start at the U.S. Open in his attempt to become the fourth man in the Open era to reach all four Grand Slam finals in a single season.

The 2012 champion at Flushing Meadows and seeded No. 2 this year, Murray beat Lukas Rosol 6-3, 6-2, 6-2 on Tuesday night to get to the second round.

Murray lost to No. 1 Novak Djokovic in the finals of the Australian Open in January and French Open in June, and then won his second Wimbledon title last month.

Only Djokovic (last season), Roger Federer (2004, 2006 and 2007) and Rod Laver (1969, when he completed a calendar-year Grand Slam) have been to a season's four major title matches since the professional era began in 1968.

Murray has won 23 of his past 24 matches, including an unprecedented second consecutive Olympic singles gold medal at the Rio Games this month.

Earlier, in the latest outburst by Bernard Tomic, the Australian muttered at a heckler during his U.S. Open match that he was going to perform a lewd act on that person.

Tomic said after his first-round loss Tuesday that he apologized to the fan afterward. He added, though: "He definitely baited me the whole set for me to say that. But I do apologize if there were people around that heard. That's all I can say."

The 17th-seeded Tomic lost 6-4, 6-3, 4-6, 7-6 (0) to 72nd-ranked Damir Dzumhur, making 78 unforced errors.

The vulgar comments came during the first set as Dzumhur was trying to serve. Tomic later claimed he didn't remember what the heckler was saying to him.

Tomic, 23, has attracted plenty of controversy on and off the court. He has been accused of tanking matches and suspended from Australia's Davis Cup team and had multiple run-ins with police. His father, who serves as his coach, was given an eight-month suspended sentence and banned from the ATP Tour for a year in September 2013 for assaulting his son's former hitting partner.