MARIA SHARAPOVA’S comeback grand slam ended in a fourth-round defeat by Anastasija Sevastova.

The Russian won the opening set but could not keep momentum and fell to a 5-7 6-4 6-2 loss.

This was only Sharapova’s fifth tournament since her comeback from a 15-month doping ban in April and she exceeded most expectations by getting this far.

This was a step up for Sharapova after her victories over Timea Babos and Sofia Kenin, with Sevastova through to the fourth round in New York for a second straight year.

The Latvian defeated Garbine Muguruza and Johanna Konta 12 months ago and has since climbed to 17th in the world rankings.

Sevastova cannot match Sharapova for power but possesses excellent court craft and a wicked drop shot.

In the first set that was not enough to combat the Sharapova forehand. The Russian broke early, was pegged back to 4-4 but then clinched it with a series of vicious groundstrokes.

Sevastova stuck to her game-plan, though, probing away intelligently, forcing Sharapova to put all the pace on the ball and dragging the Russian all around the court.

The Latvian broke the Sharapova serve in the third game of the second set, and the five-time grand slam champion found her big weapon a little less reliable.

There was nothing wrong with her improvisational skills, Sharapova playing two left-handed forehands - her second and third of the match - in a single point to hold for 4-3.

Her big chance to level came in the following game but, when her return on break point was called out, Sharapova chose not to challenge.

Replays showed it was in. Sevastova ran with her luck to win the set and, after Sharapova had taken a long toilet break, dropped just one point in the opening three games of the decider.

Sharapova took a medical time-out to have treatment for what appeared to be a blister on her finger and immediately retrieved one of the breaks, Sevastova suddenly looking very tight.

But the 27-year-old quelled the nerves and won the final three games to set up a quarter-final clash with Sloane Stephens, who continued her remarkable comeback from a year out with a foot injury by beating Julia Goerges.

Meanwhile, Denis Shapovalov’s US Open adventure ended in the fourth round with defeat by Pablo Carreno Busta in the men’s.

Shapovalov looks every bit a future grand slam champion given his armoury of exciting weapons and competitors’ mentality.

But he will have to wait a little longer after 12th seed Carreno Busta, the highest-ranked man left in the bottom half of the draw, battled to a 7-6 (7/2) 7-6 (7/4) 7-6 (7/3) victory.

Shapovalov hit 54 winners, more than double his opponent’s tally, but converted only three of 13 break points, and his lack of experience showed in the tie-breaks.

Carreno Busta may not be box office but he is an extremely solid player, a gritty competitor and a very good athlete.

And, while he may never have challenged for a grand slam before, he has been around a lot longer than Shapovalov and taught the youngster the lesson that it is not how many points you win but which ones.

Shapovalov, playing on Arthur Ashe Stadium for the third match in a row, got off to a flying start and served for the opening set at 5-3. But he could not take that opportunity, nor any of three set points that he created on Carreno Busta’s serve at 6-5, and it was the Spaniard who went on to win the tie-break.

The roles were reversed in the second set as Shapovalov broke Carreno Busta when he served for it but again it was the 12th seed who came out on top in the tie-break. Shapovalov had never played a five-set match in his career so a comeback was an extremely tall task.

He made a fine start to the third set by racing into a 3-0 lead but Carreno Busta pegged him back and again dominated the tie-break to reach the quarter-finals.