Medvedev is seeking to go one step further than he managed last year, when he suffered defeat to Spain's Rafael Nadal in the final.

The third seed began in confident fashion as he cruised to the opening two sets against Delbonis in New York City.

Delbonis produced greater resistance in the third set, but could not prevent Medvedev sealing a 6-1, 6-2, 6-4 victory.

Third seed Medvedev will face Australia's Christopher O'Connell in the second round.

A potential future opponent for Medvedev could be Frances Tiafoe, with the American coming from a set down to beat Italy's Andreas Seppi 4-6, 6-3, 6-4, 7-5.

The 22-year-old faces a second round clash against Australia's John Millman, who was a 6-1, 6-4, 6-4 winner against Georgia's Nikoloz Basilashvili.

The women's singles draw saw the first round exits of two veterans.

Belgium's Kim Clijsters saw her first Grand Slam match after returning from a seven-year retirement end in three sets to Russia's Ekaterina Alexandrova.

The three-time US Open champion won the opening set, but the 37-year-old was unable to prevent Alexandrova fighting back to earn a 3-6, 7-5, 6-1 victory.

Venus Williams suffered a first round defeat at the US Open for the first time in her career.

The 40-year-old American, a seven-time Grand Slam champion, was beaten 6-3, 7-5 by the Czech Republic's Karolína Muchová.