Surging Dominic Thiem among stars with difficult Wimbledon openers

Defending singles champions Novak Djokovic and Serena Williams drew easy first-round assignments at Wimbledon, at least ostensibly. So did seeded icons Roger Federer (the No. 3 seed) and Venus Williams (No. 8).

Rafael Nadal is absent (with a note from his doctor: bad wrist). Andy Murray, seeded No. 2, was tossed some red meat in the form of wild card and fellow Briton Liam Broady.

The more compelling matchups are buried in the draw, some of them pretty deeply. Here are the five juiciest first-round pairings:

1. No. 8 Dominic Thiem versus No. 80 Florian Mayer
Head-to-head: Mayer leads 1-0

Until last week, this might have appeared to be a mismatch; today it looms as an intriguing test for Thiem, the hard-charging 22-year-old Austrian power puncher. Mayer, a 32-year-old German journeyman, had won just one ATP Tour level title in his career -- until last week in Halle.

There, Mayer -- ranked No. 192 and rebounding from injury -- outfought and out-thought fellow German wunderkind Alexander Zverev to win the title. More to the point, he rolled through Thiem in straight sets in the semis. Both of his young victims had recently beaten Federer.

Thiem has gorged on tennis in 2016, playing 59 matches (47-14, four titles). Fatigue was bound to kick in at some point. But he has had time to recharge, and this is Wimbledon. Still, Mayer is a very tricky junk-baller. His heavy slice, off-pace forehands and drop shots could frustrate the straightforward Thiem. And there's this: Mayer's unorthodox game works on grass. He has been to the Wimbledon quarterfinals twice (2004, 2012).

2. No. 61 Shelby Rogers versus No. 81 Sabine Lisicki
Head-to-head: Lisicki 1-0

The question is simple: Can Rogers rekindle the magic? A few weeks ago at the French Open, the 23-year-old South Carolinian wrote an inspirational can-do story. Ranked just No. 108, she slashed her way to the quarterfinals. The tools that carried her on clay -- the big serve and punishing groundstrokes -- are just as useful on grass.

Lisicki's low ranking is misleading. She has struggled with consistency, but she has been ranked as high as No. 12, holds the record for fastest serve by a female pro (131 mph) and has hit 27 aces in a match. She has consistently punched above her weight class at Wimbledon. Runner-up to Marion Bartoli in 2013, Lisicki has given up ground each year since and has struggled lately. It's as good a time as any to play her.

Rogers was just a green 19-year-old when Lisicki beat her in their only previous meeting. If Rogers can defend and pass well -- while taking care of her own serve -- she could outfox her aggressive German opponent.

3. No. 27 Jack Sock versus No. 61 Ernests Gulbis
First meeting

One of the top U.S. hopes, Sock has had bad luck at Wimbledon. He quickly runs into one of those grass-court bombardiers who handcuffs and shuts down the kind of baseline play that guys like Sock prefer. In 2014, Sock won a match -- then got blasted off the court by Milos Raonic. Last year, Aussie Sam Groth showered Sock with aces and service winners to forge a first-round upset of the seeded American. This year, Sock's fate is only marginally better.

Gulbis is one of the most erratic players on the tour, as well as one of the most dangerous. His right arm is a cannon, his forehand is a menace. The Latvian enigma has been ranked as high as No. 10, but he has gone on losing streaks that might impress even Vince Spadea (who holds the ATP record for longest losing streak at 21 matches). The troubling news for Sock is that Gulbis might be emerging from one of his lethargic spells again.

Gulbis ended a five-tournament, first-round losing streak when he qualified for the Rome Masters and has done well since. He played three matches in Halle and has the momentum heading into this one.

4. No. 2 Garbine Muguruza versus No. 68 Camila Giorgi
Head-to-head: Giorgi leads 2-1

This one is a little more complicated than the vast difference in ranking suggests.

This is the tournament where Muguruza made her big breakthrough as last year's finalist. Now she's the French Open champion. The question on everyone's lips: Does Muguruza have a dominant champion's determination and hunger? There will be pressure on her to meet the challenge. She will also be basking in the mellow afterglow of her recent win in Paris; after all, she's still just 22. One or the other condition will exert more influence.

Giorgi's two wins over Muguruza are fairly stale bread. One was on clay way back in 2013; the other a close, hard-court battle a year later. Muguruza had little trouble with Giorgi on clay in the second round of the 2015 French Open, losing just five games. But Giorgi is one of the most explosive ball-strikers on the women's tour. The rewards are great when those heavy, relatively flat groundstrokes fall in.

Fortunately for Muguruza, Giorgi is 0-2 in her pre-Wimbledon prep work. The No. 2 seed still needs to avoid first-round jitters -- and hope Giorgi doesn't play lights-out tennis.

5. No. 4 Stan Wawrinka versus No. 63 Taylor Fritz
First meeting

Many people have remarked upon the resemblance between 18-year-old U.S. sensation Fritz and venerable Wimbledon icon Pete Sampras. This would be an excellent time for Fritz to build on the conviction that the resemblance is more than cosmetic.

If Fritz had to choose one of the active Grand Slam singles champions to play, Wawrinka would be a good pick. The Swiss two-time Grand Slam winner is least consistent at Wimbledon, his best results quarterfinal losses in the past two years. They were preceded by back-to-back first-round losses.

Wawrinka might be best of friends with Swiss compatriot Federer, but he couldn't be more different as a grass-court player. Grass just doesn't afford him sufficient time to play the way he likes.

Fritz gave Federer all he could handle a few weeks ago in a three-set, second-round loss in Stuttgart. A lean and sinewy 6-foot-4, Fritz plays an aggressive baseline game rooted in a scorching serve. But he has been rounding out his attacking skills, and has the tools to play an effective serve or approach-and-volley game.

This is a great opportunity for Fritz and a tricky matchup for Wawrinka.