Sunny skies in Belgrade allowed the semifinal lineup to be settled at the Serbia Ladies Open on Friday, as strong clay-court seasons were sustained, comebacks continued, and breakthroughs persisted.

No.4 seed Paula Badosa led the field into the final four as she continues her quest for a first WTA title. Badosa eased past No.7 seed Rebecca Peterson 6-2, 6-4 to reach her third straight semifinal on the tour, as she kept up her stellar clay-court season.

The rising Spaniard, ranked World No.44, posted semifinal showings in her last two events, in Charleston (where she defeated World No.1 Ashleigh Barty) and Madrid (where Barty got revenge).

"I've never been in a WTA final, so it's something that I'm going after," Badosa told the press, after her win. "I think I'm doing a quite good clay season, keep continuing like this, having fun.

"I have a tough match that's gonna come tomorrow. It's never easy, these kind of matches, mentally they're tough, so I will try to play my best, and I hope I can be in the final."

Badosa was rarely troubled against Peterson on service, facing just a single break point as she swept to victory after an hour and 21 minutes of play. The duo had 14 winners apiece, but Badosa kept her unforced error total down at 11, while Peterson had 17 unforced errors.

"It was a very tough match, even though the result doesn't look like that," Badosa said. "I knew I had to start very intense, and to have things very clear with her, because if she tries to get her forehand and she tries to move you on the clay court, it's tough. It was quite important I got the early break, and I could serve quite well, so that was one of the keys of the match."

Badosa did not face any break points in the opening frame as she stormed to the 6-2 lead. Things got closer in the second set, with Peterson slamming forehand winners with abandon to save break points at 2-1, then grasping her first break point of the day at 3-2.

But Badosa fired consecutive backhand winners down the line to get herself out of that jam, then calmly cruised through the remainder of the match as she notched another semifinal appearance without the loss of a set so far this week.

Badosa storms past Peterson into Belgrade semis: Highlights

Next up for Badosa will be lucky loser Viktoriya Tomova, who booked a spot in her second WTA semifinal of the season after winning two three-set battles on Friday.

Tomova has had a tumultuous path through the event, losing to Ana Konjuh in the final round of qualifying, and entering the main draw only after the withdrawal of No.1 seed Anastasia Pavlyuchenkova. Then, the Bulgarian never got her second-round match started until Friday, due to the inclement weather throughout the week.

However, Tomova came through in a big way on Friday, ousting rising Canadian teenager Leylah Fernandez in the morning, 6-3, 4-6, 6-2, then coming back in the evening to overcome qualifier Reka-Luca Jani, 6-1, 2-6, 7-5 in two-and-a-half hours.

Against Jani, Tomova was down an early break in the final set, and was unable to serve out the match at 5-4 when she had her first chance. But the lucky loser broke Jani in the final game to triumph in the barnburner, matching her clay-court semifinal showing from Bogota earlier this season.

As for Jani, she came up short in the evening, but it was still a breakthrough event for the Hungarian. Jani also needed to play two matches on Friday, and her 4-6, 6-1, 6-3 win over Anna Kalinskaya in the morning (which spanned three days due to the rain) propelled her into her first-ever WTA singles quarterfinal.

Tomova's qualifying conqueror is still active in the event, as Ana Konjuh also clinched a spot in the Serbia Ladies Open semifinals. The former World No.20 upset No.5 seed Nadia Podoroska 6-4, 6-3 in an hour and 35 minutes.

The run continues the incredible comeback to WTA-level by Konjuh, who suffered through persistent elbow injury and surgeries following her breakthrough as a teenager, which included a run to the 2016 US Open quarterfinals.

The Croat, whose current ranking of World No.188 is her best in nearly three years, is now into her first WTA singles semifinal since June 2017, when she reached the last four on the grass courts of 's-Hertogenbosch.

Konjuh, who also upset No.2 seed Yulia Putintseva in the second round, won more than half of Podoroska's first-service points, as she broke the 2020 Roland Garros semifinalist five times on the day to put together the straight-set win.

Konjuh will face another qualifier in the semifinals, but much like herself, her opponent has also had an eye-opening 2021. Maria Camila Osorio Serrano extended her own streak of going deep in WTA main draws, claiming a semifinal spot after defeating Aliaksandra Sasnovich, 6-4, 6-2.

"I've been super happy, I think I played a really good match," the Colombian told the press, after her 83-minute win. "The whole week, I've been feeling better and better, and hopefully I can feel like this tomorrow."

19-year-old Osorio Serrano has now reached the semifinals or better in her last three events. In her most recent tournament, she moved into the semis at the MUSC Health Women's Open in Charleston. Before that, she romped to the title on home soil in front of a rapturous crowd in Bogota.

Osorio Serrano broke Sasnovich seven times during their clash, as the teenager improved to 11-1 in WTA clay-court main-draw matches so far this season.  

"I feel like I was not letting myself be too defensive today," Osorio Serrano said. "I was fighting for every ball and I was not trying to go back too much, and I felt that was a key today."

Aleksandra Krunic-Nina Stojanovic - 2021 Belgrade

Aleksandra Krunic and Nina Stojanovic with their doubles championship trophies from the 2021 Serbia Ladies Open.

Srdjan Stevanovic/Serbia Ladies Open

The doubles semifinals and final also took place on Friday, and homeland heroines Aleksandra Krunic and Nina Stojanovic were crowned doubles champions by the end of the day. In the final, the No.4 seeds defeated Greet Minnen and Alison van Uytvanck, 6-0, 6-2.

The all-Serbian pairing followed their semifinal victory over Timea Babos and Vera Zvonareva earlier in the day with a win over the all-Belgian team in the final. The championship match took a hair over an hour as the victors were never broken in the romp.

"We didn't get a chance to play together in the past a lot, but I definitely believe in us," Stojanovic told the press, after the match. "Since the moment when we first stepped on the court together in our first match, I believed that we can win this tournament. That belief came true at the end, and it means a lot to me and I'm really proud of us."

"To play at home and be the first winners of the [inaugural] tournament is really a great honor," Krunic added. "I think it just makes us really happy, to have a picture next to the Belgrade sign with the trophy."

It is a fifth career WTA doubles title for Krunic, and a second doubles title for Serbian No.1 Stojanovic.