Zverev's serve was the X-factor in his quarterfinal victory over Coric

On Tuesday, the Alexander Zverev we've been waiting to see showed up in a 6-4, 6-4 victory over Nick Kyrgios at the Miami Open. Two days later, the same Zverev returned to Crandon Park in a 6-4, 6-4 win over Borna Coric in the quarterfinals.

Heading into Thursday, Coric was 2-0 in his career against the 20-year-old German. He had beaten Zverev in Cincinnati back in 2015, and also on a bigger US Open stage in 2017. Two matches might be a relatively small sample size, but the Croatian had every right to be feeling confident. But that wasn't the case tonight.

The world No. 5 came ready to play on Thursday, storming out the gates with a beautiful display of shotmaking. Zverev didn't look like a player that had been winless against his opponent coming into the match, but he looked like one that knew he had an inherent edge.

That edge came in the form of Zverev's serve and backhand. The German's serve can be tough to return on any given night, but it was on a whole other level Thursday. Sascha wasn't even giving Coric a chance to break, as he lost a total of 12 points on 53 serves. It wasn't just the velocity that was working for him, but he was on point with his placement too.

Match point from Zverev's 6-4, 6-4 win over Coric:

Zverev's backhand, meanwhile, was also punishing Coric. When the 21-year-old was able to get Zverev's serves back in play, the German was ripping his two-hander wherever the Croatian wasn't. Whether it was down the line or a short angle crosscourt, Zverev's bread and butter was working on Thursday.

For Coric, it's worth pointing out that this was a bit of an off night. The Croatian has been playing some great tennis over the past month, and it's entirely possible that he just ran out of gas. Coric is a player that is usually not going to make a lot of mistakes, but he committed far too many unforced errors on Thursday. He also won just 59 percent of his first serve points, which is a number that normally won't allow you to win a match–especially with a spot in the semifinals on the line.

Up next for Zverev is a meeting with Spain's Pablo Carreno Busta. The world No. 19 survived a roller-coaster match against Kevin Anderson in the quarterfinals earlier today, winning 6-4, 5-7, 7-6 (6).

This will be the first meeting between the two players, but Zverev shouldn't be worried about who is on the other side of the net. It's very rare that the German isn't the more talented player when he steps on a court, but he does need to make sure that he stays locked in here. This tournament isn't a major, but winning a third Masters 1000 title will at least temporarily quiet the "Zverev can't win big tournaments" crowd.

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