Karen Khachanov

TORONTO — Waiting out a near three-hour semifinal was less than ideal for Ben Shelton. A technical issue with the electronic line-calling system after his pre-game warm-up didn’t help either. 

The biggest challenge on the night came from fellow American Taylor Fritz, and Shelton was up for that too. 

Shelton was at his consistent and creative best Wednesday at the National Bank Open in a 6-4, 6-3 semifinal victory at Sobeys Stadium. 

At 22, he became the youngest American to reach an ATP Masters 1000 final since Andy Roddick did it in 2004 on the same Centre Court. 

“Tonight things were easier because everything was clicking,” Shelton said.

Shelton, the No. 4 seed, will next face Russia’s Karen Khachanov, who eliminated top-seeded Alexander Zverev of Germany in a 6-3, 4-6, 7-6 (4) marathon that lasted two hours 52 minutes.

It was Khachanov’s first win over a top-10 opponent in four tries this season.

“It’s always a question of what you do in those important moments when it counts,” said the 11th-seeded Khachanov.

The final was scheduled for Thursday night. Shelton won their lone previous ATP Tour matchup earlier this season at Indian Wells.

“He’s a rock-solid baseliner,” Shelton said. “He serves really well and he’s a great competitor.”

Both Khachanov and Zverev showed off their big service games early in their match on a warm, hazy evening at the York University venue. 

Extended rallies were rare over the early going as players settled in on the fast hardcourt. 

Khachanov took advantage of 11 unforced errors by Zverev in the first set but the German broke serve at love to take the second set. 

Zverev, the world No. 3, appeared to fade in the third-set tiebreaker while the 16th-ranked Khachanov continued his steady play. 

“The first set was terrible,” Zverev said. “I kind of gave him a headstart and he’s too good to not use that.”

In the nightcap, Fritz, seeded second and ranked fourth in the world, matched his compatriot’s power from the baseline but had some difficulty with Shelton’s touch game. 

Facing a break point at 2-3 in the second set, Fritz and Shelton exchanged potent ground strokes before the left-handed Shelton sliced a forehand that just floated over the net. 

Fritz hustled to get his racket on it but Shelton delivered a brilliant return, connecting on a backhand lob that soared over the six-foot-five right-hander and stayed in play.

“The ball sat up a little bit so that made it easier,” Shelton said. “For me, that’s a shot that since I’ve been a kid, I’ve always been really good at it.”

The seventh-ranked Shelton raised a finger in the air after the critical break. He would later seal the 78-minute victory when Fritz double-faulted. 

It was the first all-American semifinal at an ATP Masters 1000 tournament since Mardy Fish beat Roddick in 2010 at Cincinnati.

Shelton improved to 26-1 on the season when he wins the opening set.

Earlier in the day, sixth-seeded Joe Salisbury and Neal Skupski posted a 7-6 (5), 6-2 doubles semifinal win over Maximo Gonzalez and Andres Molteni of Argentina.

Salisbury and Skupski will face fellow Brits Julian Cash and Lloyd Glasspool, the No. 2 seeds, in Thursday’s final.