Marta Kostyuk of Ukraine cruised into the Mubadala Citi DC Open quarterfinals with a commanding 6-2, 6-3 upset of No.2 seed Caroline Garcia of France at the WTA 500 event on Thursday.

Kostyuk claimed a spot in her fourth quarterfinal of the year by dispatching World No.6 Garcia in just 64 minutes of play on Stadium Court in the American capital city. It was Kostyuk's first win over Garcia in their three career meetings.

"I was preparing for this match, as it was a difficult and important match," Kostyuk said afterward. "I’m glad everything worked out, and I’m happy to be in the quarterfinals."

Milestone season: Kostyuk has now won her last two matches against Top 10 opposition, having also upset Maria Sakkari in the first round of Wimbledon last month. Prior to her Wimbledon win over Sakkari, Kostyuk was 0-14 against Top 10 players.

"I gained a lot of confidence out of that [Sakkari] match, because I’d been hunting the Top 10 win for a long time," Kostyuk said. "Once I [got] it, it kind of gave me the boost and the belief that I can win these kind of matches. Hopefully it’s going to stay like this for a long time."

The 21-year-old Kostyuk has posted numerous other milestones already this season. She currently sits at a career-high ranking of No.34, and she won her first career Hologic WTA Tour singles title in Austin, Texas this March.

Tale of the tape: Kostyuk was nearly defeated in the first round this week. The Ukrainian had to save three match points before overcoming former US Open champion Bianca Andreescu in her opening match.

Kostyuk's upset of Garcia was much more straightforward. Kostyuk had 14 winners to just six unforced errors on Thursday, and she erased the lone break point she faced all day. By contrast, Garcia had 23 unforced errors and only five winners.

The Kostyuk backhand was the key shot at critical moments. She used that wing to slam a return winner on break point at 1-1 in the opening frame, earning the first of her two breaks in that set. 

At the very same juncture of the second set, Kostyuk carved a slice backhand down the line to break Garcia again. From there, the second set was nearly a carbon copy of the first. Kostyuk won 17 of her 20 service points in the second set.

Defending champion awaits: Kostyuk will now take on No.8 seed and defending champion Liudmila Samsonova in the quarterfinals. They faced off twice in 2020, with Samsonova winning both times -- once on hardcourt in Brisbane qualifying, and once on clay in Palermo qualifying.