Petra Cetkovska pulled off the upset of the tournament thus far, defeating world number five and fourth seed Caroline Wozniacki 6-4, 5-7, 7-6(1) in a late-night thriller at the 2015 U.S. Open. Cetkovska will play 26th seed Flavia Pennetta in the third round.

Before the Match

Cetkovska and Wozniacki had met three times before, with the Dane leading the head-to-head 2-1. The former world number one defeated the Czech in straight sets in the first two meetings but Cetkovska, who is making a come back after a hip injury, won their last meeting on the grass of Wimbledon in 2013. The 30-year-old has always given the Danish number one problems every time they played, because of how she was able to maneuver the ball from side-to-side with so much power.

Cetkovska Comes Back from a Break Down to Win the Opening Set

To begin the match, Wozniacki held to 30. The fourth seed knew how dangerous Cetkovska was and she was ready to pounce on any opportunities that were given to her. The Czech was misfiring quite a bit in the early stages of the match, as she was broken to 30 in her opening service game. Now up 2-0, Wozniacki had to save two break points before holding and consolidating the early break. Trailing 0-3, Cetkovska desperately needed a hold. One could sense that she was a little nervous in the beginning of the match, but eventually she settled in to get on the board. One game can make a big difference as in the next game, the world number 149 had opened up her shoulders and was swinging more freely. As a result, she was able to recover the early break.

Now trailing 2-3 on serve, Cetkovska looked to have settled into this second round encounter but more errors began to fly off of her racquet, as she was broken once more. Wozniacki was looking to hold serve to consolidate the break, just like she did in the third game of the set. However, the Czech’s easy power was making the Dane run from side-to-side, and that put Cetkovska exactly where she wanted: inside the court. Forcing errors off of the world number five, the Czech number thirteen broke straight back and now trailed 3-4. In the next game, Cetkovska held to 15 to level the match at four-games-all. Wozniacki hadn’t held her last two service games and it was clear that it would be another uphill battle for the former world number one as Cetkovska earned herself two break points. The Czech from Prostejov only needed one break point as she converted it to give herself a 5-4 lead. From 2-4 down, Petra ran off three games in a row and would attempt to serve out the opening set. Cetkovska had no trouble closing out the opening set, doing so at love to win her fourth game in a row and with it, the set, 6-4.

Wozniacki Fights Back from a Double Break Down to Steal the Second Set

The second set began just like the end of the first as Wozniacki’s woes on serve continued. The Dane was broken to start the set but there wasn’t much she could do as Cetkovska was just playing some of her best tennis. The Czech, who reached a career high of number 25 in the world in June 2012, continued to put her foot on the accelerator. Giving Wozniacki no big opportunities or gifts, Cetkovska consolidated the break to go up 2-0. Things went from bad to worse for the fourth seed as despite her best efforts, she was broken for the fifth consecutive time, and the underdog coming into this match went up a double break. Could Wozniacki fight back?

Judging by the next game, it looked like she would. Giving no free points away, the former world number one recovered one of the two breaks but still trailed 1-3. Not hindered by getting broken, Cetkovska continued to play aggressive but she was also mixing it up by hitting high, loopy balls and drop shots, which sent Wozniacki scrambling. Her efforts were rewarded as she broke once again, this time to love. Petra Cetkovska was just two games away from upsetting the world number five. But could she get over the finish line?

Being the fighter that she is, Wozniacki refused to go down without a fight. Continuing to get every ball back, the Danish number one was able to draw errors off of Cetkovska’s racquet. As a result, she broke once again and now trailed 2-4. The big question was: Could she hold serve now? The Czech made it really hard for the fourth seed to hold serve but part of it was the Dane’s fault. Despite having a good first serve percentage, Wozniacki could not place her serve well enough to gain the upper hand in most of the rallies in her service games. On top of this, Wozniacki’s second serves averaged 65-70 miles-per-hour which allowed Cetkovska to tee-off on her second serve returns.

The Czech had four break points in the next game but she was unable to convert any of them, as the Dane got every ball back and Cetkovska began to misfire. Wozniacki would go on to hold and would now trail 3-4, but just by a break this time. It seemed that the former world number 25 had lost the plot as her forehand began to betray her in the important moments. In the next game, four consecutive errors from Cetkovska handed Wozniacki the remaining break of serve. Now tied at four-games-all, the momentum had swung in favour of the fourth seed.

All of a sudden, the Dane was able to hold serve easily, increasing her lead her lead to 5-4. After Cetkovska had won seven games in a row, Wozniacki won four in a row. The Czech managed to stop the route as she held comfortably to level the second set at five games apiece. Wozniacki replied with an emphatic and rare hold to love as she went up 6-5 in the second set. Now serving to stay in the set again, Cetkovska managed to fend off her Danish counterpart’s first set point but not the second, as Wozniacki came back from a double break down to win the second set, 7-5.

Cetkovska Plays Perfect Tiebreaker to Win the Match

In the entire third set, there were no breaks of serve. Wozniacki had to save a total of four break points in the entire set, but time and time again she was able to come out of those service games to lead by a one game advantage. However, it was Cetkovska who was very impressive on serve in her opening four service games. The Czech only lost two points and stayed with the former world number one. The question was: Who would crack first?

In the 10th game when Wozniacki was leading 5-4, with Cetkovska serving, the Dane earned herself her first match point of the match. However, the Czech refused to go away as she continued to play aggressive tennis under pressure. With a smash winner, the former world number 25 saved a match point and would go on to hold to level the match at five-games-all. Despite squandering her first match point,Wozniacki continued to serve well in the important moments to go up 6-5. The next game proved to be one of the biggest of the match as Wozniacki had two match points when Cetkovska was down 15-40, but the Czech hit two brilliant forehand winners under pressure to save both of them. A couple of points later, Wozniacki had a third one but that was saved with another winner from Cetkovska. The Czech number 13 was playing well above her ranking against the world number five as she held serve to force a final set tiebreaker, as the clock ticked past midnight.

In the tiebreaker, both women traded mini breaks before Cetkovska got a crucial one at 2-1 to go up 3-1. From there, the world number 149 began to swing freely again to play some of the tennis that got her up a set and a double break in the second set. Cetkovska got an insurance mini break, giving herself a 4-1 lead. Could she close it out this time?

With some big hitting and serves, Petra Cetkovska consolidated the two mini breaks to go up 6-1 in the tiebreaker, giving herself five match points after saving four of them. On the Czech’s first match point, Wozniacki hit a backhand down the line into the net and Cetkovska had done it. She had defeated the fourth seed 6-4, 5-7, 7-6(1) to advance to the third round of the U.S. Open for the first time of her career.

This is also only the second WTA-level main draw win of 2015 for Cetkovska, to show you what a difficult year she’s had. En route to this three hour and five minute victory, the Czech hit 61 winners to 60 unforced errors, a true example of just how aggressive she was against Wozniacki.