The second serve is not the first shot you think of when looking at a tennis player, but Alexander Zverev’s tremendous improvements on this critical shot have helped him ascend to the Top 10.

“I know that there is going to be a great serve,” he said in a news conference at Indian Wells, Calif. “My second serve, I trust a lot. My second serve I think is a really good and solid one.

A couple of points later, Norrie bounced the ball 23 times. Jarry then took an age between a first and second serve, before Norrie again followed suit.