San Francisco Frontiers - Defending champion Medvedev out of Shanghai Masters

The Russian fell apart in the second set after Korda won the first on a tiebreaker taken to the brink to finish 7-6 (10/8).

Medvedev then fell three games behind in the second set, but looked like he might be about to make a comeback with a blistering win in the fourth game.

But the American fought back, taking the next game, and Medvedev grew increasingly agitated, gesticulating in frustration and bouncing his racket on the ground in anger.

Korda ended up defeating the world number three in straight sets, finishing the second 6-2.

"I feel awesome, I played an incredible match," said 23-year-old Korda, thanking the crowd for their enthusiasm.

The match's thrilling rallies drew gasps and exclamations from spectators as the two battled it out.

"We played a really good tiebreaker, you know, it was up and down from the beginning... I'm happy to be on the winning side of it!" Korda added.

Medvedev had said the game would be "interesting" for him beforehand, referencing the fact that Korda beat him at their last meeting.

- Ruud through -

World number nine Casper Ruud continued his smooth progress through the tournament with another straight-sets win, this time against the United States' Christopher Eubanks.

Ruud appeared in control throughout against the 32nd-ranked American, with the third-round match ending 6-4, 6-2.

The Norwegian said he was pleased he'd held his nerve against a "tough, fast" player.

Ruud said he was looking ahead to qualification for the ATP Finals in Turin, which takes place in November and features the world's best eight qualified players.

"I know every week is going to matter, and that's motivating and a bit stressful at the same time, but I like the battle and the competition," he said.

Two top-20 players exited the tournament in the second round Sunday.

Britain's 16th-ranked Cameron Norrie was defeated by the United States' JJ Wolf, ranked 51st.

And 59th-ranked Lorenzo Sonego took out Frances Tiafoe, the world number 13, 2-6, 6-2, 6-3.

China Open champion Jannik Sinner takes on Argentina's Sebastian Baez in the evening session.

K.Hernandez--SFF