PARIS -- On Saturday, as the No. 5-ranked player in the world traded fierce groundstrokes with his coach, many of the people standing between Court Nos. 4 and 5 had their backs turned to him, apparently finding a women's doubles practice more interesting.
The several dozen people sitting close to Court 5 enjoyed the sunshine, chatting with their neighbors, reading L'Equipe, munching sandwiches and, in a few cases, napping. No one seemed terribly interested in Juan Martin del Potro, who walked off to a smattering of applause.
About five minutes later, when four-time defending champion Rafael Nadal took the court, chaos ensued. Hundreds of spectators applauded wildly, jammed the stands and, playing paparazzi, snapped cell phone photos for posterity.
Anonymity, at this early stage of his career, is fine with Del Potro.
"It's OK with me," he said earlier in the tournament. "I try and play my matches, and then, you know, we have the top four for this tournament.
"That's OK if the press has decided to focus on the top four."
Del Potro, a 20-year-old from Argentina, has come farther faster than anyone to the height of professional tennis. Friday's men's semifinals here at Roland Garros are his first chance to make a lasting impression.
No. 2 Roger Federer versus No. 5 Juan Martin del Potro
Federer has never won the French Open, and this clearly is his best opportunity. Of course, he's been this close before. This is Federer's fifth consecutive appearance in the final four. Only Eric Sturgess of South Africa, who went 0-for-6 from 1947 to '52, suffered more.
Instead of Djokovic at this stage of the draw, Federer gets Del Potro, a man he has beaten all five times they've played; in sets, the count is 12-0.
"With his game, he does everything perfectly," Del Potro said. "His game is much of a problem to me, and this is why I never won when I played him."
Earlier this year, Federer strafed him in the Australian Open quarterfinals, allowing the 6-foot-6 Del Potro only three games in a three-set mauling. Three games. More recently, on the clay in Madrid, Federer beat him by a more respectable 6-3, 6-4 score.
"I'm looking more [like] Madrid," Federer said. "I think clay suits his game even more. He's really improved a lot in the last year. I'm sure it's going to be a difficult match."
Del Potro, who dislikes playing on clay, has worked hard on his movement and now feels he can play roughly the same game that wins him matches on hard courts. Maybe he would have a better chance if he weren't so reverential toward Federer.
"We feel the pressure of the fans; everybody wants Roger to win this tournament," Del Potro said. "But if I can't win this tournament, I want to see next Sunday Roger with the trophy.
"It's going to be vey difficult. We all know how he plays, and we all know what he wants to achieve here now that Rafa is no longer here."
Greg Garber: Federer in three. He's thisclose to making history.
Bonnie D. Ford: Federer in three. Won't be denied at this point.
You read right; Nadal and Murray did not keep their appointment with this top-half semifinal. Few imagined this matchup -- including Gonzalez.
"It is a big surprise," Gonzalez said after beating Murray in a four-set quarterfinal match. "Had someone told me I would reach the semifinals of a Grand Slam and I would have to play [Soderling], I don't know if I would have believed it."
This promises to be more competitive than Federer-Del Potro. Gonzalez holds a marginal 4-3 lead in head-to-heads -- but has won the past four. Still, they haven't played since 2007.
This one is tough to call because Soderling knocked off Rafa, then followed it up with a lights-out performance against Nikolay Davydenko in the quarters. The question: How much gas does the Swede have left in his tank?
He's been on court for exactly 4½ more hours than Gonzalez, and at some point, you think he suddenly will realize where he is. Soderling has never been this far before, not even close, while Gonzalez reached his third French Open quarterfinal, to go along with his silver medal from the Beijing Olympics and the runner-up trophy from the 2007 Australian Open, where he lost to Federer.
That experience could be telling.
"Hopefully, I can use that," Gonzalez said.
Greg Garber: Gonzalez in four. Been here before.
Bonnie D. Ford: Soderling in four. Has the hot hand.
Greg Garber is a senior writer for ESPN.com.