Juan Martin del Potro turns up the heat to reach Wimbledon last 16

WIMBLEDON -- Right from the start, there was no doubt about the attitude or intentions of Juan Martin del Potro. As chair umpire Carlos Bernardes recited the pro forma details that accompany the prematch coin flip, del Potro kept his eyes fixed on the turf at his toes, hitting spirited air forehands and backhands, never once lifting his face to make eye contact with his opponent, Benoit Paire.

The routine wasn't meant to intimidate Paire. It's just that del Potro, the No. 5 seed at Wimbledon, is all business once he steps on a tennis court. That's also something that hasn't always been said of Paire, the charismatic Frenchman, so it's hardly surprising that del Potro and that big serve slowly suffocated Paire in the stifling London heat in just under two and a half hours, 6-4, 7-6 (4), 6-3.

The win on Court No. 2 Saturday moved del Potro into the fourth round, one step closer to perhaps checking off a prominent box on his post-injury to-do list. Del Potro has a Wimbledon-worthy game anchored in a massive forehand and serve ("his serve is like crazy," Paire said). But "Delpo" missed three editions of Wimbledon with serial wrist injuries that required three career-threatening surgeries. Unable to hit any backhand but a slice because of the condition of his wrist, he also was beaten here in the third and second rounds respectively in the past two years.

This is a different year, though. A new dawn. The first year since 2013 -- the year del Potro lost to Novak Djokovic in the the longest semifinal in Wimbledon history (4 hours, 43 minutes) -- that all his weapons are in good working order.

That's why del Potro was able to tick a different, significant box in March when he beat Roger Federer in a third-set tiebreaker to claim the Indian Wells title. Ever the classy guy, Federer swallowed back the bile of defeat and said, "What's interesting is that he [del Potro] put himself out there with no double-hander almost, but was just happy to slice and still take losses. ... he was happy enough playing this way, which I admire a lot."

In Paire, del Potro was facing one of the most colorful characters on the tour. He's lean and broad-shouldered, 6-foot-5, with a bushy brown beard topped these days by a thatch of platinum-dyed hair. Overall, he looks like a dip-top ice cream cone, which is appropriate for a guy who's capable of making shots as sweet -- or zany -- as anything produced by a Federer or Kyrgios.

At 29, Paire is the same age as del Potro. But he's experienced nothing like the hardships that del Potro has known. The impediments that have kept Paire from reaching his ceiling were mental rather than physical. He had a streak of negativity as wide as an airport runway, and his shot selection could have been drawn from a hipster's upturned fedora -- as is often the case with players young, gifted and athletic. He had a particularly bad attitude toward grass.

"Well, I was young and I was a little bit stupid," he explained. "So that's why I didn't like the grass."

But Paire has matured. He reined in some of the wilder circus shots as well as his temper, mastered the art of movement on grass. His results at Wimbledon improved dramatically. Last year, he lost in the fourth round to Andy Murray. No wonder del Potro kept his head down and focused on the task at hand, despite saying of Paire, "I know him well, it's always a pleasure playing against him."

The matchup played out under a blazing sun. By the time del Potro bulldozed his way to a win in the first set, it seemed that if the spectators didn't pass out from the heat, they would from the overpowering smell of sunblock.

Paire, who has been suffering with a meniscus tear in his left knee, has been wearing a heavy wrap extending from his mid-calf to well under the hem of his shorts, with small cutouts for his knee. By the start of the second set the tape was soggy and fraying. With the full beard and the ragged bandage he looked less like the No. 47-ranked tennis player than a casualty of war.

It only got worse from there, if not quite as bad as it was for the fan who passed out in the stands and held up the match for about 10 minutes in the third set. Paire had major problems with the sun in the seventh game of the first set, surrendering the critical break. He fell heavily while changing direction at 4-2 in the second set. Worrying about his knee, he ended up broken and del Potro kept an iron grip on the tiebreaker. Finally, Paire suffered a mysterious injury to the ring finger of his right hand -- even he doesn't know what -- two points from the end of the match and it had him literally hopping around in pain as del Potro dropped the curtain with an ace.

Del Potro knows that due to the limited grass schedule, you have to make hay at Wimbledon while the sun shines. With No. 53 Gilles Simon his next opponent, he has a fine chance to make the quarterfinals, especially with his big-bore backhand firing again.

"I'm hitting more often with the two-handed backhand, which was good for me the whole game," del Potro said. "On this surface, I can mix it up with the slices and hit hard when I have the chance to make a winner with a two-handed backhand. I think I'm improving all my game when I have my backhand working good. It's pretty important for myself."

Del Potro added that he knows his game and feels it's well adapted to the grass.

"I had my chances to win here a few years ago when I lost against Djokovic [in] the semifinals. But he was playing so good. I don't know how far I will [get] in this tournament, but I have confidence with my game at this time."

Just as important, del Potro is as healthy as he is confident. And that may be the best news of all for the star-crossed Argentine.