Juan Martin del Potro

While Justine Henin’s victory over Yanina Wickmayer stole the show in the women’s singles portion of the 2010 Australian Open, Sunday’s men’s singles showdowns hardly disappointed, either. Two titantic tilts headlined a delicious day (and night) of action at the Melbourne Park tennis complex.

In the match of the afternoon, reigning U.S. Open champion and No. 4 seed Juan Martin del Potro shook off a wrist injury and – as was the case in his second-round victory over James Blake – displayed the fighting spirit and hustle of an elite tennis player in his match against No. 14 Marin Cilic. There wasn’t much wrong that Delpo did at Hisense Arena. He slugged. He sprinted. He served huge (19 aces plus many more service winners) and ran down dozens upon dozens of shots.

There was only one problem (aside from his less-than-100-percent wrist, of course): Cilic did everything Delpo did, only better.

Cilic – who reached his first major quarterfinal at last September’s U.S. Open, lost to Delpo when he arrived at the round of eight in New York. On this Sunday Down Under, Cilic learned the lessons of that four-set loss and outlasted his credentialed counterpart in a five-set marathon.

Cilic battled both his nerves and his very gallant foe to dig out a 5-7, 6-4, 7-5, 5-7, 6-3 triumph in 4 hours and 38 minutes. Having beaten Andy Murray at the U.S. Open, Cilic showed a measure of staying power in the sport by knocking off the man who has climbed the charts more quickly than anyone else under age 23.

The Croatian wobbled at the business end of the first and fourth sets, and he converted only three of his first 14 break point chances in a match he largely dictated, but when the fifth set came calling, Cilic became a cool customer. He broke for a 3-1 lead in the final set and proved to be nearly impregnable whenever he had to save a break point on his own serve.

One uses the word “nearly” because del Potro had one chance to get back on serve near the very end of the match.

With Cilic trying to serve out the showdown at 5-3, del Potro gained an ad-out break point chance. On that point, delpo received a short reply from Cilic in the middle of a rally, a sitter that the Argentine would normally crush into the corner for a winner, or, at the very least, a point that would put him in a winning position. Instead, Delpo netted the ball, and Cilic knew he had to pounce on the opportunity. The Croatian, given a lifeline at deuce, convincingly claimed the next two points and grew up before the tennis world’s eyes.

And to think, that was just the first of two showstoppers in Australia.

In a night match that followed the Henin-Wickmayer epic, Andy Roddick earned the right to face Cilic after stopping Fernando Gonzalez in “only” 3 hours and 25 minutes, 6-3, 3-6, 4-6, 7-5, 6-2. Roddick teetered on the edge of disaster, as Gonzalez – leading two sets to one – had a few chances to gain a break lead in the fourth set and serve out the match.

However, the American’s serve held firm when he most desperately required something special on his signature shot. Gonzalez then stood one point from a fourth-set tiebreak on multiple occasions, but Roddick wiped out a batch of game points for the Chilean and took the fourth set when Gonzalez made a poor decision.

In position to make a play on a ball that landed on the line but was initially called out, Gonzo refused to hit the ball. When the Hawkeye replay system showed that the ball had in fact clipped the line, chair umpire Enric Molina properly awarded the point – and the game, and the set, 7-5 – to Roddick.

The fifth set was anticlimactic, as Gonzalez lost the fire and focus he possesses in short spurts but can rarely sustain. Gonzalez got irritated and allowed himself to implode, while a calmer and fitter Roddick protected his serve and found the finish line first.

That finish line was crossed after 1 a.m. Melbourne time on Monday, at the end of a wild ride in the men’s singles bracket.