ST. PETERSBURG, Russia -- No.4 seed Aryna Sabalenka notched another victory during her first-ever week in the Top 10, as the Belarusian eliminated Russian qualifier Ekaterina Alexandrova, 6-3, 6-4, to reach the semifinals of the St. Petersburg Ladies Trophy on Friday.

"I couldn’t find the rhythm of the game and it was always up and down, but finally I was happy that I finished it on my side," Sabalenka told the press, after the match.

"I started really, really slow and I couldn’t put the ball in," Sabalenka added. "After two games, I make a decision, ‘Well, let’s start to start playing!’" she said with a laugh.

20-year-old Sabalenka needed 86 hard-fought minutes to make her second semifinal showing of the season, adding to her title run in Shenzhen last month. Sabalenka also beat Alexandrova en route to the Shenzhen singles trophy, in the second round of that event.

The hard-hitting affair finished with Alexandrova having 22 winners, one more than Sabalenka. But the Belarusian kept her unforced errors more under control than the Russian did, as Alexandrova shot 30 miscues to Sabalenka's 23. Each set was closely contested, but it was Sabalenka who won more key points, breaking the Russian four times. Alexandrova assisted Sabalenka with 11 double faults.

"It was a lot of crazy shots today," Sabalenka admitted. "That’s why I probably couldn’t find the rhythm of the game, because it was, like, unforced error from her, then winner from her, then winner from me, then an ace, then a double fault, and you’re always like, ‘What’s going on here today?’ I’m happy that finally I found a way out to win this match."

Alexandrova gave Sabalenka all she could handle in the early stages of the opening set. The Russian was taking the ball early and matching the seeded player power for power, and she broke Sabalenka in the opening game, then consolidated for a 2-0 lead.

But Sabalenka struck back in a long game at 2-1, eventually taking Alexandrova’s serve on her third break point of the game when a backhand by the Russian clipped the netcord and dribbled over the net barely wide. Sabalenka began to hit her spots with more precision, and broke Alexandrova for a 4-2 lead with an error-forcing backhand.

At 5-2, Alexandrova did well to end a five-game streak by Sabalenka, holding serve and saving a set point with a well-placed delivery in the process. Sabalenka, however, coolly served out the set in the next game, finishing with a deadly forehand winner. 

Alexandrova made her path to a comeback more difficult when she fired three double faults en route to being broken in the opening game of the second set. The Russian also had three double faults in her subsequent service game, but was able to rebound via some brilliant backhands to hold serve and stay within one break of Sabalenka.

That hold proved to be crucial when Sabalenka got tentative with her shots at 3-2, allowing Alexandrova to crack some powerful returns and clamber back on serve at 3-3.

At 4-4, the Russian seemed to have momentum, but at 40-15, she blasted an easy overhead into the net at 40-15. That gave Sabalenka new life, and from deuce, the Belarusian hit two stellar groundstrokes to earn a break of service out of nowhere. Sabalenka took that inch and made it a mile, finishing the match in the next game with consecutive backhand winners.

Sabalenka will next face either No.2 seed Kiki Bertens of the Netherlands or Russian hope Anastasia Pavlyuchenkova in the semfinals. Pavlyuchenkova is one of four Russian players to reach the last eight in St. Petersburg.