Britain's Katie Boulter and Sonay Kartal were both beaten in the opening round of the US Open, the latter losing out in a bizarre match with 18th seed Beatriz Haddad Maia in which both players suffered badly with cramp.

Haddad Maia edged a tight opening set 6-3, before Kartal battled back in impressive fashion to romp through the second 6-1, only for the British No 2 to struggle first with cramp early in the decider.

With Kartal limited, Haddad Maia raced into a 4-0 lead with a double break, and was 30-0 up on her next service game before she suddenly also cramped up.

It led to Kartal taking the next four points to claim one break back, Haddad Maia barely able to move, but the Brazilian summoned the strength from somewhere to take the next two games and clinch victory.

Both of the final two games went to multiple deuces as the two players struggled to move freely; Kartal had opportunties in both, but Haddad Maia eventually converted her third match point to secure a 6-3 1-6 6-1 win.

Boulter's Grand Slam struggles continued as she was beaten by Ukrainian 27th seed Marta Kostyuk in straight sets, 6-4 6-4.

Boulter, the British No 2, hasn't been in the third round of one of the majors in eight attempts, the 2023 US Open the last time she did so.

Boutler battled back from a break down in both sets, only to hand the advantage back immediately to her opponent on both occasions.

The 29-year-old showed further fight when saving five match points on her own serve down 3-5 in the second set, while she then quickly went 0-40 on Kostyuk as she threatened to restore parity and kick-start a comeback bid.

But Kostyuk repelled that threat, taking the next six points to secure her safe passage through to the second round.

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