Andy Roddick's career is now over thanks to his loss to Juan Martin Del Potro in the Round of 16 at the U.S. Open. The legacy he leaves behind is clear: he was the last American to win a Grand Slam event and the last to be the No. 1 player in the world, both achievements coming in 2003.

With that kind of success early in his career, the expectations were high but Roddick never won another major, one of the countless victims of playing in the same era as Roger Federer. Roddick's career is perhaps defined as much by his losses -- one in particular comes to mind -- as his wins.

Like any top-level tennis player, there were plenty of great moments in his career that we'll remember now that his playing days are done. So without further ado, the top five moments of Andy Roddick's career.

Honorable mention: The press conferences

You certainly have to give Roddick one thing, he was always honest. He had an ornery streak in him with the media that he also had with many a chair umpire, but his self-deprecating humor and brutal honesty were always welcome ... and entertaining.

No. 5: 2001 Miami Masters

Pete Sampras. (Getty Images)

At the same event where Roddick played his first ATP-level event, Roddick announced himself as an up-and-coming star in the sport and in the American ranks. He was granted a wild-card spot in the event and was placed in the same section as the defending champ and American legend, Pete Sampras. Good luck with that, right?

No luck needed. Roddick took out Sampras in straight sets in the third round. In total, Roddick went through three seeded players without losing a set to make the quarterfinals in Miami before running into Lleyton Hewitt, who eventually stopped Roddick.

It was a career-launching tournament for Roddick. It wasn't as if Sampras was done at that point in his career. He still had a U.S. Open title to come in his illustrious career (and Sampras finished as the runner-up in the Open later in the year, losing to Hewitt).

No. 4: 2007 Davis Cup

Roddick and his teammates celebrate USA's first Davis Cup title in 12 years. (Getty Images)

For U.S. tennis, the Davis Cup had long been an expectation. Over the history of the event, no country has been better than the USA. But by 2007, the drought for the USA was up to 12 long years between titles and the pressure was building. That's entirely too long.

So Roddick was tasked with leading the American squad in the 2007 competition as the U.S. came in as the six seed. The Americans got past the Czech Republic, No. 4 Spain and Sweden to reach the final, where the No. 1-ranked Russian team awaited. Fortunately for the U.S., the final was held on its terms, in Portland, Ore.

Roddick was given the task of taking the leadoff lag against Dmitry Tursonov and he did exactly what was needed, breezing through in straight sets. After victories by James Blake and the Bryan Brothers, it was done, the U.S. ended the drought. It was also the last time the USA has won the Davis Cup.

No. 3: 2003 Australian Open quarters

The scoreboard tells the tale after the record match. (Getty Images)

By this point Roddick was known in tennis, but he was still looking for that major breakthrough. It came Down Under in 2003, in what would turn out to be the best season of his career by far.

He came into the Aussie Open with the No. 9 seed, landing in the same draw as No. 1 and the home favorite Hewitt. Only they never met because Hewitt was tripped up in the fourth round by Younes El Aynaoui to set up the quarterfinal that would go down in the history books.

Before John Isner ever met Nicolas Mahut, this was the definition of a marathon match. The players split the first four sets, Roddick taking the second and staying alive by winning the fourth. On to the fifth set and the land of no tie-breakers they went .

After 2 hours and 23 minutes, Roddick finally came out with the victory, taking the final set 21-19 to reach the semifinals, the first of four times he would go that far in Melbourne. The match set the record for the longest set in a Grand Slam -- which has obliterated by Isner/Mahut. Roddick would go on to fall in the semifinal to Rainer Schuttler but the memory of the quarters would not be forgotten.

No. 2: 2009 Wimbledon final

Roddick applauds after losing the final to Federer. (Getty Images)

Here you have a defining moment of a guy's career coming in a loss. But it was that spectacular of a performance by Roddick against Roger Federer, particularly after Roddick took out home-court favorite Andy Murray in the semis.

Consider a bit of the backstory. Despite the fact that Roddick only ever won the U.S. Open among the majors, he had more chances at Wimbledon. Of the four finals that Roddick had reached before this point, two of them were on the grass in London. All of those losses -- including the fourth finals loss at the U.S. Open in 2006 -- came against Federer. Roddick had come so close on multiple occasions but couldn't beat Federer and earn that second Slam. This was his best shot.

Roddick won the first set, breaking Federer late in the set to take it 7-5. Despite not being broken on his serve, Roddick lost the next two sets, both in close tie-breakers. Roddick then earned the second break of the match in the fourth set to take it 6-3 and go to a deciding set, sans tie-breakers of course.

Federer had the advantage of serving first in the set so every hold by him put the pressure on Roddick's racquet to stay alive. If he was broken there was no chance to respond. Considering there had only been two breaks of serve all match, both Roddick breaking Federer, it seemed like we were going to be in for a long match, and we were. Federer's serve remained locked in and he began chipping away at Roddick, getting close on a few games but it wasn't until they were at 20-19. There's something about that 21-19 score for Roddick ...

In that 40th game of the set, Federer finally cracked Roddick to win Wimbledon for the sixth time in his career -- his third victory over Roddick in a final. Roddick was struck with the awful misfortune of having held his serve for every game until the last. That was 41 straight service games held, but asking for 42 was just too much.

It was Roddick's best and last real shot at a Slam. Instead he had to settle for being the loser in one of the greatest matches every played, the longest final in Grand Slam history.

No. 1: 2003 U.S. Open championship

Roddick can hardly contain his emotions after winning the '03 U.S. Open. (Getty Images)

Naturally, the one breakthrough that Roddick did have is tops. How could it not be? Many will argue it was that Wimbledon loss, but his title in 2003 was just as great. Iit was just longer ago and thus easier to forget.

The final match itself wasn't all that spectacular. Roddick took it to Juan Carlos Ferrero 6-3, 7-6 (2), 6-3. But it was a lot more than just the win. It was a sign of what was to come -- or so we hoped -- for American tennis. People wondered how life after Sampras and Agassi for the United States would be. They were ready to embrace the next American star and Roddick showed he was it.

It was the culmination of what turned out to be Roddick's best year of his career at the age of 21. On the strength of the U.S. Open title, Roddick finished the year as the world No. 1, the last American male to hit that mark.

It was also a terrific scene when that final ace was recorded. Roddick was incredibly emotional, running into the stands to climb into his box and hug his family and friends as well as his then-coach, Brad Gilbert. The emotion was so real and strong.

This is what the scene looked like, the final game of Roddick's one and only championship with a hyped up crowd in New York cheering him on. This is Roddick's crowning moment.