World number one Novak Djokovic succumbed under pressure to lose against Daniil Medvedev in the semi-finals of the Cincinnati Masters.
Djokovic lost the tie 6-3, 3-6, 3-6 against the ninth seed Russian.
In the women's section, Ashleigh Barty was denied a chance to reclaim the WTA world number one ranking.
She was beaten by veteran Svetlana Kuznetsova.
Here are the details.
Medvedev stunned Djokovic to set up a title showdown with 16th-seeded David Goffin.
The Belgian defeated France's Richard Gasquet 6-3, 6-4 to reach his first ATP Masters 1000 final.
Despite winning the first set, Djokovic saw Medvedev turning things around in a dramatic fashion.
"It's a great feeling to win and beat the number one player," said Medvedev.
"I don't know how I turned it around, I was so tired after the first set and I thought I might not be able to keep up the intensity," said Medvedev.
With the US Open coming up, Djokovic claimed that he will want to take the positives from the Cincinnati Masters.
"Today I did lose a tennis match, but I didn't do too much wrong. So I'll take that and I'll move forward to New York and have a good practice week," he said.
Djokovic will be wanting to win the third Slam in 2019.
Meanwhile, Kuznetsova outclassed Barty in straight sets in the WTA Cincinnati Masters semi-finals.
She won the duel 6-2, 6-4.
Barty's plans to reclaim the world number one title from Naomi Osaka got derailed.
She had to qualify for the finale.
Osaka will enter the US Open as the world number one.
Kuznetsova will be bidding for her 19th career title.
"It's amazing to be playing here again on the center court after the injuries of the last few years. I must admit, I did enjoy the time in Moscow, sleeping in my own bed. I was glad to have the time off," said Kuznetsova.
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