LONDON, July 4 (Reuters) - ⁠Second seed Elena Rybakina's hopes of a second Grand Slam title this year ⁠and taking over as world number one ended at Wimbledon on Saturday ‌as she faded to a 7-6(4) 6-1 third-round defeat by inspired Belgian Elise Mertens.

The Kazakh never recovered from losing a tight first set on a tiebreak and 25th seed Mertens seized control thereafter to reach the ​last-16 at Wimbledon for the fourth time.

"I knew I ⁠had to keep my focus, especially ⁠at the beginning of the second set," Mertens, who described it as one of her ⁠most ‌memorable victories, said. "Really had the fire in me today."

Rybakina, who added this year's Australian Open title to her 2022 Wimbledon crown, needed to reach at ⁠least the quarter-finals to have a chance of overhauling Aryna ​Sabalenka at the top of ‌the WTA rankings.

But she produced a flat performance on Court One against the ⁠wily 30-year-old ​Mertens whose greater variety proved decisive in only her second win over Rybakina in nine meetings.

After a stunning start to the year with her Melbourne Park triumph and a runner-up finish to ⁠Sabalenka at Indian Wells, Rybakina's season has cooled off ​dramatically.

"If I knew why, I wouldn't be in this situation right now," she said, when asked what had happened. "I have been working well, I think, in the past weeks.

"Definitely I need ⁠to analyse and change something, because it's not working.

"I just try to move on. I lost so many times. I'm sure I'm still going to keep losing. It's impossible to win everything. I'm of course upset, but it's not going to take more than ​one, two days (to get over it)."

Mertens, a reigning Wimbledon doubles ⁠champion, won nine points in a row during one dominant spell in the second set ​and although she showed a few nerves when serving ‌for the match she ended the contest ​with an ace.

She will fancy her chances of posting a best-ever Wimbledon run with Czech Marie Bouzkova up next.

(Reporting by Martyn Herman, editing by Pritha Sarkar)