WIMBLEDON, England - Four women had a chance to overtake World No.1 Ashleigh Barty at Wimbledon but after an upset-filled Round of 16, the 23-year-old will retain the top spot heading into the North American hard court swing.

After becoming just the second Australian to hold the WTA No.1 spot, Barty went into Wimbledon looking to hold off four women for the top spot: No.2 Naomi Osaka, No.3 Karolina Pliskova, No.4 Kiki Bertens, and No.6 Petra Kvitova. 

The 23-year-old Aussie ended No.2 Naomi Osaka's 21-week reign at the top of the rankings after running off 12 consecutive match-wins to win back-to-back titles at Roland Garros and the Nature Valley Classic in Birmingham two weeks ago. 

Champions Corner: New No.1 Barty reflects on rapid rise - 'I'm not really sure what's going on!'

Barty saw her 15-match win-streak come to an end against America's grass-court stalwart Alison Riske in the Round of 16 on Wimbledon's Manic Monday. Riske, who has now won 14 of 15 matches on grass this season, ended Barty's quest for the "Channel Slam", coming back from a set down to win 3-6, 6-2, 6-3. 

Despite the loss, Barty will retain the No.1 ranking after No.3 Karolina Pliskova saw her title hopes dashed by her compatriot Karolina Muchova. In a tight affair, Pliskova lost 4-6, 7-5, 13-11 in the longest women's match at Wimbledon this year, clocking in at 3 hours and 17 minutes. Pliskova's loss guaranteed Barty would finish the tournament at No.1.

[This post has been updated to reflect the results after the Round of 16. The scenarios before the tournament follow below.]

No.1 Scenarios: Projected Point Table 

No.2 Naomi Osaka must reach at least the third round to have a chance at returning to No.1. The reigning US Open and Australian Open champion is defending 130 points over the fortnight, having lost to eventual champion Angelique Kerber in the third round last year.

Like Barty, the 21-year-old is also looking to make the second week of Wimbledon for the first time in her career. In her only grass event before Wimbledon, Osaka lost to Yulia Putintseva in the Round of 16 at Birmingham. Osaka and Putintseva will face-off again in the first round here. 

No.3 Karolina Pliskova must reach the semifinals to have a chance at returning to No.1 for the first time since September 2017. The Czech is coming off a near-perfect run to the title at the Nature Valley International in Eastbourne over the weekend, where she defeated reigning Wimbledon champion Kerber in the final to capture her third title of the season.

Champions Corner: Pliskova's perfect preparation - 'I never had a week like this'

Pliskova's best result at Wimbledon came last year, where she advanced to the Round of 16 before losing to Bertens. She is defending 240 points over the fortnight. 

No.4 Kiki Bertens needs to win the title to have a chance to move to No.1 for the first time. The 27-year-old, who won the biggest title of her career in May at the Madrid Open, is currently the highest-ranked Dutchwoman in WTA history. Long considered a clay-court specialist, Bertens signaled her recent evolution into an all-surface threat here last year, where she ousted Venus Williams and Pliskova to advance to her first Wimbledon quarterfinal, where she lost to Julia Goerges.

The Dutchwoman is defending 430 points. Bertens has enjoyed a strong grass season, making her first grass-court final in s'Hertogenbosch and the semifinals in Eastbourne, where she lost to Pliskova. 

No.6 Petra Kvitova also must win the title to have a chance to move to No.1 for the first time in her career. The two-time Wimbledon champion, who kicked off her Slam season with a run to the final of the Australian Open, is defending just 10 points over the fortnight after taking a first-round loss last year to Aliaksandra Sasnovich.

Wimbledon will be Kvitova's first grass event of the year, having been forced to withdraw from her last two tournaments at Roland Garros and Birmingham due to a forearm injury.