Juan Martin del Potro and Tomas Berdych open fire in Rotterdam

The centre of attention since the Rotterdam 500 got under way has been everyman and top seed Roger Federer.

But although he has been practising, signing and talking away the hours since he arrived at the Ahoy Centre on Monday, it was not until Wednesday evening that he began his campaign to defend the title he won here seven years ago.

It was, in fact, the day that all three big guns both opened their account here and closed out round one.

Before the star of the show—and crowds close around Federer wherever he appears—could tidy up the first column of the draw, though, the two heavyweights in the bottom half of the draw, No2 seed Tomas Berdych and No3 seed Juan Martin del Potro, made their very different ways through their opening matches.

Berdych has come to Rotterdam with a 5-0 match-win record, taking the Montpellier title and then winning his singles match (as well as doubles with Radek Stepanek) to help take the Czech Republic into the Davis Cup quarter-finals.

He faced his compatriot, world No 77 Lukas Rosol, and their very different rankings hit home towards the business end of the opening set: Berdych broke to take it 6-4 and then raced through the second set, 6-2, taking more than 60 percent of the points.

Del Potro, however, survived an altogether bigger test of his mobility and fitness. Playing in Rotterdam for the first time, he had already talked of the challenge of bending his large frame to handle the low bounce of these indoors courts.

And despite breaking back into the top 10 last month for the first time since wrist surgery in 2010, the Argentine had his work cut out against world No47 Michael Llodra, a man who fits these indoor courts like a glove.

Llodra was the champion in Rotterdam in 2008 and his fast-paced serve-and-volley game, played with the left hand, takes time away from his opponents and keeps them moving back and forth to retrieve short low balls and sliding backhand slice.

So it may have been kids’ day at the Ahoy—schools close on Wednesday afternoons here—but it was far from kids play for del Potro. It was clear from the start that he intended to take that initiative away from Llodra by attacking the net himself.

He had already displayed some greatly-improved volleying skills in his hour’s practice on Monday against Federer, and he also looked very fit and fast. What’s more, he ducked out of Davis Cup duties at the weekend to focus on his hard-court preparation without the diversion of clay.

His serve-and-volley attack took him through a high-quality first set: He served at 76 percent and didn’t face a single break point. He converted the second of his two break chances in the ninth game and served out, 6-4.

Llodra, though, upped the pace at the start of the second set, attacking the net not just on his own serve but on del Potro’s. It earned him four break-point chances in the second game, forcing del Potro to scurry around the net, reach for smashes and find the big serves at just the right time. The Argentine held, only to face another break point in the fourth.

Again Llodra failed to convert and it looked as though his chance was gone when he immediately went down 0-40 on his own serve. He survived with typical Gallic flair: touch volleys, angled put-aways and a wonderful whip of a single-handed backhand. They headed to a tie-break and, against the odds, it was Llodra who held his nerve and his serve to ease the set, seven points to three.

The final set saw Del Potro find his first serve again—back up to 74 per cent—and he did not face a single break point. Llodra, to his credit, only faced one, but it was at the most crucial moment, in the 10th game: match point. With impeccable focus, the big man from Argentina snatched it to advance to a second-round meeting with qualifier Karol Beck.

He knew it had been a test and knew he had done well to survive:

“Very tough first match, very difficult game for me. Lot of serve and volley, drop shots, slices, it’s not easy that way for me. I was really focusing in the last game of the match, two passing shots with my backhand, and that gave me confidence to win this match.”

It may have been a hard-won victory but it perhaps marked the beginning of an evolution in the Del Potro game, one that will give him extra depth as he makes his inexorable rise back towards the place in the top four that he left almost two years ago.

Asked about his improving serve and volley game, he suggested it was a necessary development:

“I don’t serve and volley like [Llodra] but working on that could be a new part of my game, if I use more serve and volley for this kind of surface or for grass, and that helps me for this year, of course.”

The tactic also revealed an evolution in the physical skills of del Potro. He moved forward more quickly, reacted to Llodra’s angles quickly and picked up shots around the net with more ease than he once did.

And while his body language is slow and considered, the fun of this event, on this particularly boisterous day, did not pass him by.

“It’s nice: So many kids walking around and talking, it’s funny for us, that they’re enjoying the kids day today. Also a big crowd, almost full. It’s really nice. Of course, if I win, it’s better!”

Federer opened the evening proceedings against Nicolas Mahut—a match played out in front of a record tournament crowd of almost 10,000, more even than last year’s final.

The Swiss set the tone with the first point of the match, on the Frenchman’s serve: a scorching winner. Mahut held out until the third game but was then broken to love and Federer served out the set in 30 minutes, 6-4.

The second set was more competitive: Mahut scored some lovely volley winners with a right-handed version of Llodra’s earlier game. But Federer knocked on the door in the seventh game with four break point chances and finally made the killer blow in the ninth game to serve out the match, 6-4.

Federer was due to play another former champion, world No31 Mikhail Youzhny, but the Russian pulled out with injury and Federer has agreed to play a super-tie-break set ahead of the revised evening schedule with Dutch wild card, Igor Sijsling.

Meanwhile, round two was already under way before Federer had finished his press duties: Nikolay Davydenko took to Centre Court in search of the form that seems to have deserted him since winning Munich last April.

If he finds it in the next couple of matches, it could earn him a semi-final place against Federer. With two wins out of their 18 meetings, he will have to find some huge firepower, too.