Carlos Alcaraz continued where he left off on the British grass by starting his Queen's title defence with a straight-set victory over Argentina's Francisco Cerundolo.

The 21-year-old Spaniard won 6-1 7-5 in his first match on grass since lifting the Wimbledon title last year.

Alcaraz won the third major of his career on the French Open clay earlier this month, before switching back to the surface where he has played the least.

It looked a comfortable transition initially, but he ran into difficulty in his first-round match against 26th-ranked Cerundolo.

But the world number two recovered to earn his 12th straight win on a grass court.

"It doesn't matter what tournaments I'm playing, or everything I have achieved, I am still learning," said Alcaraz.

"Every time I step on a grass court I need to learn how to move better and play better."

Alcaraz dropped just 14 points in a one-sided first set before fighting back from a break down at 5-2 in the second.

Cerundolo could not serve out at 5-3 and had three set points at 5-4.

But he struck two backhands into the net, either side of Alcaraz saving the second with an ace, as the Spaniard escaped to hold for 5-5.

That proved costly as Alcaraz broke for 6-5 and served out to love.

"The first match in every tournament is never easy but even more difficult here on grass," said Alcaraz.

"Starting the grass season you want a good result and you have to deal with the expectations you put on yourself.

"It was a good test against Francisco. I'm really happy with what I've done and hopefully can keep going."

Alcaraz will play new British number one Jack Draper in the second round after the 22-year-old beat Argentina's Mariano Navone.

Sinner battles back to win at Halle

New world number one Jannik Sinner had to come from behind to win his opening match at the Halle Open in Germany.

The Italian, who replaced Novak Djokovic as the top-ranked men's player following his run to the French Open semi-finals, recovered to beat Dutchman Tallon Griekspoor 6-7 (8-10) 6-3 6-2.

"It was for sure mentally tough," Australian Open champion Sinner, who faces Hungarian Fabian Marozsan next, said.

"I was 5-1 up in the tie-break in the first set. But this can happen, especially on this surface, it can go very, very fast.

"I was struggling in the second set, 0-40 down on my serve. If he makes that point, it is even more difficult."

There were also victories for German second seed Alexander Zverev and Greek sixth seed Stefanos Tsitsipas.

Zverev, beaten by Alcaraz in the French Open final earlier this month, also had to come back from a set down to win 6-7 (5-7) 6-3 6-4 against compatriot Oscar Otte.

Tsitsipas came through two tie-breaks against German Henri Squire to clinch a 7-6 (9-7) 7-6 (7-2) victory.

However, Russian fourth seed Andrey Rublev is out following a straight-set loss to American Marcos Giron.

Rublev, runner up in 2021 and last year, was beaten 6-4 7-6 (7-5).