LONDON, Great Britain - Former semifinalist Magdalena Rybarikova is back to her winning ways at Wimbledon.

The unseeded Slovak sent the first seeded player tumbling out of the Championships with a 6-2, 6-4 first round upset of No.10 seed Aryna Sabalenka on Monday. 

In a match in which she led throughout after Sabalenka held serve to begin the match, Rybarikova broke twice in each set, and held off a surging Belarusian late in the second set, who continued to apply pressure after getting one of the breaks back. 

The Slovak, well-known for her grasscourt pedigree even before a stunning run to the semifinals while ranked World No.87 in 2017, entered Wimbledon in sputtering form on her preferred surface. 

The 30-year-old was runner-up to Alison Riske at the ITF W100 in Surbiton in the first week of the grass season, but was forced to retire against Astra Sharma in the qualifying tournament of the Nature Valley Open with an illness, and suffered a second-round upset at the hands of Beatriz Haddad Maia in her last London tune-up event as the top seed at the ITF W100 in Ilkley.

Nonetheless, she found a similarly out-of-form Sabalenka on the other side of the net: though the Belarusian reached the quarterfinals last week in Eastbourne, saving a match point to upset defending champion Caroline Wozniacki along the way, the Nature Valley International marked just the second time she'd won consecutive matches since March.

Related: Sabalenka topples Wozniacki in Eastbourne epic

Using her variety to disrupt Sabalenka's rhythm off the ground, Rybarikova also won 83 percent of the points when she landed her first serve in the match.

The Slovak hit 18 winners to 13 unforced, as Sabalenka racked up 28 unforced to just 16 winners over the course of 70 minutes of play.

More to come...