Kiwi Lulu Sun has ended her grand slam drought with a first-round victory at the US Open.

Sun had suffered four straight first-round exits since her run to the quarter-finals at Wimbledon last year, which has seen her world ranking drop to 164 in the latest rankings.

But she bettered Colombian world No 63 Camila Osorio 6-4, 2-6, 6-0 on court five in an impressive display.

Playing in a US Open main draw for just the second time in her career, Sun went out to a 5-2 lead in the first set before being broken for the first time in the match. But she held her composure to take out the set 6-4.

Twenty-three-year-old Osorio came out firing in the second set, going out to a 4-0 before eventually winning 6-2.

But Sun returned the favour with a fast start in the deciding set, herself going out to a 4-0. Osorio rolled her ankle in the final point of the fourth game needing a medical timeout. She returned to the court but wasn’t moving as freely as the Kiwi closed out the victory.

She will either 19th seed Elise Mehrtens or American Alyssa Ahn in the second round.

Sun, who was ranked as high as 39 in the world just over a year ago, dropped 62 places in the most recent world rankings after losing the points she earned from reaching the Monterrey Open last year, when she was knocked out at the round of 32 last week.