Sharapova still has work to do

Here are five things we learned on Day 1 at Wimbledon:

1. Maria, you know, can't win easy these days

Maria Sharapova grinded her way to the French Open quarterfinals, winning four straight three-set matches. Guess what? The 2004 Wimbledon champ had another tough one at Wimbledon on Monday, rallying from 4-1 down in the first set to overcome Ukrainian Viktoriya Kutuzova, the top seed in qualifying, 7-5, 6-4. She also saved a set point.

Sharapova, recently back from a serious shoulder injury, admitted there was still "work to be done" on the fitness front.

Here's what she made of Kutuzova, the world No. 79:

"I played against a really solid opponent, you know, who went for many shots and who's just being really aggressive, you know, playing like she didn't have much to lose, which she didn't.

"And, um, you know I knew she already had, you know, three good matches in qualifying … her game suits the grass pretty well."

We know.

2. Five-set thrillers are on the board

And who would have thought two-time Wimbledon quarterfinalist Feliciano Lopez, seeded 21st, would come up short against Slovakian baseliner Karol Beck, ranked 143rd? (Yes, the same Beck who received a two-year suspension for testing positive for the banned substance clenbuterol in 2005.)

Lopez lost 1-6, 7-5, 6-3, 4-6, 10-8 in nearly four hours on Court 18, paying the price for a 1-for-7 showing on break points in the final set.

So no Rafa and no Lopez. That leaves Fernando Verdasco as the lone Spanish lefty capable of going deep.

Verdasco predictably eased past British wild card James Ward.

3. Karlovic can win at Wimbledon

The wait is over for Ivo Karlovic.

The 6-foot-10 serving machine won his first match at Wimbledon since 2004 -- yes, your eyes are not deceiving you -- by knocking off Slovakian qualifier Lukas Lacko 6-3, 7-6 (4), 6-3.

Karlovic has worked on all parts of his game in recent seasons, but those aces do help, and he delivered 32 against Lacko. Karlovic excitedly pumped his fist upon completing the win.

The Croat, twice a winner of grass-court titles, lost to Fabrice Santoro and Stanislas Wawrinka, as well as the unlikely duo of Daniele Bracciali and Simon Stadler, since venturing to the fourth round five years ago.

Karlovic looms in Roger Federer's quarter.

4. Tennis is a dangerous game

Just ask British hope Laura Robson.

Last year's junior Wimbledon winner, making her Grand Slam debut, had to scurry to fend off a serve from Slovak Daniela Hantuchova while warming up. The ball looked destined to smack the 15-year-old between the eyes.

Robson, busy taking high school exams a few weeks ago, struck an ace on the first point and acquitted herself well, though she eventually fell 3-6, 6-4, 6-2 on the new Court 2.

"I played a really good match," said Robson, who was born in Melbourne, Australia. "It's different to juniors, but it's not that much different. I mean, if I would have got killed love-and-love, then yeah, I'd be coming in here with a different opinion."

5. The grass is greener for the Americans

Who misses the clay? Certainly not the U.S. contingent in London.

Americans went 5-2 on the opening day of the Wimbledon fortnight, all in straight sets, highlighted by Serena Williams' comfortable win over Portuguese qualifier Neuza Silva and Mardy Fish's victory against an ailing Sergio Roitman, who trailed by two sets, then retired 4-1 down in the third (shoulder).

Fish and his big serve have never progressed past the third round at Wimbledon, which is a little strange. And he knows it.

"A couple of third rounds isn't exactly how I'd envision Wimbledon going for my career when I started playing well," said Fish, who was ranked as high as 17th five years ago. "I thought I was going to win Wimbledon when I was 10 years old, that I'd be pretty great. But I feel like this tournament just suits my game perfectly."

Vince Spadea ousted Chilean clay-courter Paul Capdeville, and fellow veteran Jill Craybas, Williams' conqueror en route to a fourth-round appearance in 2005, downed Bulgarian Tsvetana Pironkova; Sam Querrey bypassed Thai lucky loser Danai Udomchoke.

The two losers were U.S. No. 2 James Blake, a finalist at last week's AEGON Championships, and Singapore-born qualifier Michael Yani. Italian Andreas Seppi overcame Blake, and Yani, a product of Duke University, fell to German Simon Greul.

Critic's choice

No. 6 Andy Roddick vs. Jeremy Chardy: With Rafael Nadal out of the picture, Roddick has a clear path to the semis as long as his right ankle is fine. Or does he? Chardy, a talented Frenchman, is only two spots off his career-high ranking of 39th set last month.

ESPN.com prediction: Roddick in four.

Ravi Ubha is a frequent contributor to ESPN.com.