"I wasn't able to play with that fire that I have in all my matches", Del Potro added, saying however that 34th-ranked Basilashvili "played unbelievable".
Wozniacki broke Sevastova twice in her first three service games, but lost serve in the seventh game and needed to save three break points to prevent the Latvian levelling at 4-4.
Wozniacki was cruising as she won four of the last five games in the first set and then went 4-1 up in the second.
Osaka's shock triumph - at such a young age and against one of the greatest tennis players of all time - propelled her into the limelight. "I'm just, like, 'Oh, I guess I have to do more, to be better'". "I needed to really work it, to work hard, win the points". Caroline played unbelievable today, it's always tough playing against her and I have never won.
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Right now nobody knows anything about it, but there are some pretty bad stories going around. "I do not like it". The ministry did not say when the premises would be searched.
Unseeded Sevastova needed one hour and 31 minutes to win and reach the final, the biggest in her career.
"I also want to thank and apologise to Anastasija for today".
"Unfortunately, I have been playing through pain in my back this whole week", the world number six said in a subsequent statement released by organisers.
"Then after number one in the world, I wanted to win a Slam, then I wanted to lift trophies".
Sevastova, 28, will find herself just outside the top 10 in the rankings after her run in the Chinese capital.