To mark the end of a record-setting 2019 season, is counting down our picks for the best WTA Upsets of the Year. Check out our Top 5 Grand Slam Matches and our Top 5 WTA Matches here.

Coming in at No.4 is Victoria Azarenka's second-round defeat of two-time defending champion Elina Svitolina at the Internazionali BNL d’Italia, where the Belarusian battled past inclement weather, late into the night, to seal a dramatic turnaround. 

Top 5 WTA Upsets of 2019:
No.5: Kenin def. Barty, Toronto

WHAT HAPPENED: Neither a pair of rain delays, nor one stern fight from two-time defending champion Elina Svitolina could deny Victoria Azarenka a third Top 10 victory of 2019 in Rome.

The former world No. 1 outlasted Svitolina in a wild, 4-6, 6-1, 7-5 second round match that lasted well into the evening at the Foro Italico in May, as she denied the Ukrainian an opportunity to become the first woman in over 20 years to win three straight titles in the Eternal City.

Azarenka came from a set down and saved a match point late in the third set, ultimately winning five straight games, to seal the victory in two hours and 14 minutes and improve her head-to-head record against Svitolina to 3-0.

Read the match report: Azarenka edges defending champ Svitolina in rain-delayed Rome battle

Despite the Belarusian's unbeaten record against Svitolina, she arrived into the match as an underdog, having been given a wildcard into the Premier 5 event where Svitolina boasted a 10-match winning streak.

Owning a mixed record on clay overall even at the height of her powers at the top of the WTA rankings, the two-time Australian Open champion had some of her best successes in Rome, where she reached the final in 2013, the semifinals in 2009 and two other quarterfinals.

With the first set in the books to Svitolina, but following a break of serve for Azarenka to begin the second set, the pair sat through a break rain delay - before more inclement weather arrived five games later.

They returned to the court shortly after 10:30 p.m. local time, and though the former World No. 1 won two more games to send the match to a decider, it was Svitolina who put herself on the precipice of victory by winning five of the first seven games in the third.

Having already won five straight games to take the second set, Azarenka pulled off a more dramatic escape with her back against the wall, as she saved a match point on her serve at 5-2, and broke the Ukrainian when she served for the match herself in the eighth game. 

2019 Rome highlights: Azarenka edges defending champ Svitolina

WHAT THEY SAID: Though they partnered on the same side of the court in doubles earlier in 2019 in Indian Wells, Azarenka had not faced Svitolina in nearly four years - with both of her prior victories against the Ukrainian in 2015 coming with Svitolina ranked outside of the Top 10. 

“It was such a dramatic match - it was a lot of breaks and stuff with the rain, and that was quite difficult to deal with,” Azarenka reflected after the match.

“But I’m happy I was able to just block it out, play my game, survive the match point, and then pick it up from there to play great tennis.

“Overall it was a high quality match. I’m happy with my performance, and I’m happy to be through and I’ll try to get better in the tournament.”

WHAT IT MEANT: The loss was part of a spring swoon for Svitolina, who struggled with a knee injury for much of the spring and early summer, and lost her first match at five of six events following the BNP Paribas Open in March, before Wimbledon in July.  

Following a 6-3, 6-3 victory over Venus Williams in the first round of the French Open, her lone official victory in that span, Svitolina reflected:

"I didn't really think about my losing streak because I think all the matches that I played, except Madrid maybe, was close and I felt not too bad. Sometimes in few matches in the past two months, I had where I was not thinking about what I had to do on court... so it's not easy, but I learned a lot during these two months, and I tried to have a right mindset, which going to help me to handle this."

Ultimately, it was that mindset that let to a late-season surge for the year-end World No.6, who reached back-to-back Grand Slam semifinals in London and at the US Open, and who returned to the championship match at the season-ending WTA Finals. 

Conversely, the victory served as one of the high points of Azarenka's season, which ended with her ranked World No. 50 following a high of World No. 38. 

Two of the Belarusian's trio of Top 10 victories in 2019 came on clay, as she also beat Karolina Pliskova at the Porsche Tennis Grand Prix in Stuttgart, but she proved unable to score another victory against the elite from then on, despite leading by a set - against Pliskova in the aforementioned quarterfinal round in Rome, and against Naomi Osaka at Roland Garros - in two of three overall encounters. 

A quarterfinal showing in Rome was her best result at Grand Slam, Premier Mandatory or Premier 5 level in 2019, though she reached her first final in nearly three years at the International-level event in Monterrey, Mexico before losing to Muguruza, and won her first title since the birth of her son, Leo, in 2016, in the doubles event in Acapulco