LONDON, United Kingdom (AFP) — Carlos Alcaraz warned his Wimbledon rivals that he "feels great" on grass after the world No. 2 defied his expectations by winning the Queen's Club title for a second time.

Alcaraz battled to a bruising 7-5, 6-7 (5/7), 6-2 victory over Czech world number 30 Jiri Lehecka in the final of the Wimbledon warm-up event on Sunday.

The 22-year-old has extended his career-best winning streak to 18 matches, putting him in the perfect position to defend his Wimbledon title.

Alcaraz has won the French Open, the Rome Masters and Queen's during his blistering run.

But the five-time Grand Slam champion had arrived in west London concerned about his ability to make the tricky transition from the clay-court season to the unique demands of the brief grass campaign.

Underlining the difficulty of the task, Alcaraz is the first player to win Roland Garros and Queen's back to back since Rafael Nadal in 2008.

"I'm going to say it's really complicated, the switch from clay to grass in just a few days, because that's the time I had before the tournament began, just two days of practising," Alcaraz said.

"So I came here with no expectations at all. I came here with a goal to play two or three matches, try to feel great on grass, and give myself feedback on what I have to improve.”

"But I got used to the grass really quick, and I'm really proud about it. My goal was complete, and I'm not talking about lifting the trophy or making the final.”

"It was just to feel great, to feel really comfortable on grass once again."

For a player raised on the clay courts of Spain, Alcaraz has become a formidable force on the lawns of Queen's and Wimbledon.

He is only the third Spanish man to win four grass-court tournaments after Nadal and Feliciano Lopez.

"It's great to be with Rafa and Feli, such great players from our country," he said.

"Hopefully, now I will not stop here. Hopefully, keep going."

A key part of Alcaraz's winning formula is his ability to switch off from tennis after tournaments to ensure he is refreshed when he returns to the court.