REUTERS: Naomi Osaka battled back from a set down to defeat Anett Kontaveit 4-6 6-2 7-5 on Wednesday and reach the Western & Southern Open semi-finals for the first time while British number one Johanna Konta also advanced.
Japan's Osaka trailed 2-0 in the second set, but she stepped up her serving and cut down on unforced errors to reel off six straight games.
The final set looked headed for a tiebreaker when Kontaveit rushed out to a 40-15 lead while serving at 5-6 but fourth seed Osaka fought back and completed the comeback when the Estonian sent a backhand wide on match point.
"For the first set and honestly a couple of games in the second I was just really being down on myself and super negative," said Osaka.
"For me, I just didn't want to, you know, if I had to lose a match, I didn't want to lose a match on that note. Yeah, I just tried to be more positive and pump myself up."
Next up for the twice Grand Slam champion is a meeting with Belgian Elise Mertens, who needed just over an hour to defeat qualifier Jessica Pegula 6-1 6-3 and reach her first Premier 5 semi-final.
Eighth seed Konta punched her ticket to the semi-finals with a 6-4 6-3 win over Greece's Maria Sakkari, who entered the match fresh off a win over Serena Williams for one of the biggest wins of her career.
A tight first set ultimately came down to one break of serve, which Konta converted in the third game. Konta broke two more times in the second, including in the final game where she secured the win after a Sakkari double fault.
Up next for Konta, who is rounding into form with each match, is a clash with former world number one Victoria Azarenka, a 7-6 6-2 winner over Ons Jabeur of Tunisia.
The tournament, the final tune-up before the US Open, is being played at Flushing Meadows in New York this year instead of Cincinnati due to the COVID-19 pandemic.