World No.3 Naomi Osaka kept an unblemished run going to book her spot in the Gippsland Trophy semifinals on Friday, after the three-time Grand Slam champion eased past Irina-Camelia Begu 7-5, 6-1.

"My opponent today, she was really tricky for me," Osaka said in her on-court post-match interview. "I’ve never played her before, so just to be able to not have to play that 10-point tiebreaker, for me, I’m really relieved."

The weather threw a wrench into the schedule as on-and-off rain caused the Margaret Court Arena roof to be closed, but that did not prevent Osaka from attaining a 73-minute victory, where she hit 22 winners to just 11 unforced errors.

"I feel like it’s more interesting that it’s different," Osaka said. "If I were to come out and for every day to be the same, I’m the type that gets bored, so a new challenge every day is definitely more interesting."

No.2-seeded Osaka’s victories this week have now extended her unbeaten streak to 14 consecutive match-wins, as the reigning US Open champion has not lost since a Billie Jean King Cup upset to Sara Sorribes Tormo 12 months ago.

2021 Gippsland Trophy Highlights: Osaka streaks into SFs with Begu win

In a competitive opening frame, Osaka saved two break points to hold for 5-4 and prevent Begu from serving for the one-set lead. Osaka eventually leaped to a 0-40 lead at 6-5 before Begu double-faulted to hand over the opening set.

The second set was more straightforward for the three-time Grand Slam champion. Serving for the match at 5-1, Osaka slammed three straight unreturnable serves to reach triple-match point. On her first opportunity, Begu sent a forehand long. 

The former World No.1, who triumphed at the Australian Open in 2019, will take on No.7 seed Elise Mertens in the semifinals.

Ekaterina Alexandrova stunned Simona Halep in the Gippsland Trophy quarterfinals.

Photo by Getty Images

Alexandrova upsets Halep 

No.9 seed Ekaterina Alexandrova needed exactly an hour Friday night to record the biggest upset of the week of WTA 500 events, securing a 6-2, 6-1 win over top seed Simona Halep at the Gippsland Trophy.

After falling behind 2-0 to start the match, the Russian rallied to win 11 of the next 12 games on Margaret Court Arena, improving her head-to-head record against the former World No.1 to 2-1 and advance to her third semifinal in the past 12 months.

"Playing semifinals tomorrow, it'll be just great for me," Alexandrova said after the match. "I just tried to play my best. I was kind of nervous at the start because this court isn't my lucky one, but after two games, I won one game and I felt much better."

Tripling Halep's total of winners (18-to-6), the Russian's aggressive play also afforded her a staggering 10 break point opportunities in the match.

She successfully converted five of them, and also saved five of the six that she herself faced to secure her second victory over a Grand Slam champion in as many matches.

Alexandrova will next face former Top 15 player Kaia Kanepi for a spot in the final of the WTA 500 event.

The Estonian advanced without hitting a ball on Friday when No.8 seed Karolina Muchova withdrew with a left abdominal injury.

Mertens holds off Svitolina

Elise Mertens needed six match points to finally put away Elina Svitolina on Friday to reach the semifinals of the Gippsland Trophy.

Mertens ultimately prevailed 6-3, 5-7, [10-6] and will take on the second-seeded Osaka on Saturday at Melbourne Park.

“I thought this was never going to end,” a relieved Mertens, the seventh seed this week in Melbourne, said to the remaining crowd afterward. “Had to keep trying, and that’s what I did.”

Mertens looked in command early. The 25-year-old Belgian was up a set and two breaks, but failed to end the match seamlessly.

She had three match points in the eighth game of the second set and two more in the tiebreaker, all of which she lost, until her sixth, when Svitolina dumped a forehand into the net.

Mertens has won two of three career meetings against Osaka.

2021 Gippsland Trophy Highlights: Mertens edges Svitolina in thriller