KEY BISCAYNE, Fla.— World No. 63 Denis Kudla held his own on Saturday against 12th-seeded Milos Raonic at the Miami Open, but wasn’t able to capitalize on the big points, falling 7-6 (4), 6-4.

Before the match, the American knew he had to take advantage of his opportunities, few as they may be against such a high-caliber opponent.

“I have to take control of the baseline because that’s definitely my only chance," Kudla said after winning his first-round match over Hyeon Chung. "Because you’re not going to take away [Raonic’s] serve, it’s a little too tough I need to take advantage of every opportunity I get.”

Raonic’s serve was more than “a little too tough”—it was impenetrable. He won 80 percent of his first-serve points, served 11 aces and wasn't broken once. Kudla did his best with his own serve, giving away just one break, but even that was one too many.

Decked out in Lacoste and sporting a backwards hat and scruffy beard, the Virginia native gives off a strong “bro” vibe. It was in sharp contrast to the stoic Raonic, looking the part of a Canadian patriot with a red-and-gray New Balance kit accessorized with a bright red arm sleeve. What began as an injury prevention became a Twitter sensation (#BelieveInTheSleeve), and is now integral part of Raonic’s ensemble.

“It started as a health thing, but then it quickly became a comfort thing for myself,” Raonic said. “It’s sort of like when I put on the sleeve it’s pretty much a way of letting myself know it’s match time. It might sound silly, but I think it’s kind of part of my preparatory routine.”

Silly or not, the sleeve seems to have worked, along with Raonic's famous mouth guard. He began wearing the protective accessory at the start of 2016 for a teeth-grinding habit, and wears it almost 24/7 with the belief that it will help balance his entire body.

He has a 13-2 record this year, with a title in Brisbane, a semifinal finish at the Australian Open, and a final-round appearance in Indian Wells.

But as soon as the Raonic breakthrough—a big title, perhaps a Slam—seems imminent, an injury always seems to halt his progress at the top. Last year the 25-year-old underwent foot surgery and dealt with a back injury that eventually pushed him outside of the Top 10, and this year he’s already experienced hip adductor and leg injuries. There was even a chance that Raonic might not play Miami with the leg injury.

“I got diagnosed [after Indian Wells] and I was pretty much told it was no kind of rupture or tear, more kind of a strain of some damaged fibers,” Raonic said. “I was told that if it looks like its getting better day by day, which it is, that I can challenge myself to make a go here.”

Getting through a challenging opening-round match was a good start. With no breaks exchanged in the first set against Kudla, the match went into a tiebreaker, which quickly went in the way of the more experienced Raonic. Kudla’s serve was earning him a few easier points, but any longer rallies inevitably ended with a Raonic winner, often from a booming forehand or with a put-away volley. The Canadian won 12 of 18 points at net.

Kudla had a look at two break points early in the second set at 2-1, 15-40, but couldn't convert. The Canadian’s big serve bailed him out of trouble, and Kudla went on to let up just a bit—but enough—to lose his first and only service game of the match. With that, the second set went briskly to Raonic. The final point was Raonic’s 11th ace.

Despite the loss, Kudla showed he could play with the big boys, though that’s something he already knew from reaching the fourth round at Wimbledon last year.

Raonic next faces another American in Jack Sock, who defeated a recently chatty Sergiy Stakhovsky, 6-3, 3-2 (ret).

“[Sock] obviously likes to dictate and control with his forehand,” Raonic said. “For me, I think it’s important to serve well. The usuals—I’ve got to take care and control the center of the court and make a lot of returns.”

Raonic leads the head-to-head with Sock 6-1 after winning their last six meetings. But their last two matches were at Masters 1000 events and ended in third-set tiebreaks. Will Raonic oust another talented American? What we do know is that it will feature huge serves, slap-shot forehands, and, of course, that sleeve.