Korda beats Shelton in Shanghai battle of young guns

It was the first all-American quarter-final at a Masters 1000 event for six years and it did not disappoint, with the explosive Shelton finally taking his fifth chance to win the opening set having earlier failed to serve it out. 

Korda, two years older at 23, hit back strongly and Shelton - a US Open semifinalist last month - appeared to be flagging physically when he trailed by a break in the deciding set. 

But he fought back to level and saved five match points from 1-6 in the deciding tiebreaker before Korda clinched his sixth opportunity. 

"It's super cool," said Korda. "I played a really high level. Ben did as well. We had a lot of great points out there and hopefully it's the first of many battles that we play against each other. 

"He's such an electric tennis player and it was a lot of fun to share the court with him today." 

In the last four, Korda will take on Polish No.16 seed Hubert Hurkacz, who ended the surprise run of Hungarian Fabian Marozsan with a 4-6 6-1 6-3 victory.