PARIS -- Guillermo Canas has built a career, and now a comeback, on tirelessly running down any ball in his zip code. He makes every shot about the journey as well as the destination, routinely letting out a small, gasping groan of effort on his way to the ball and another one when he strikes it.
Yet for all his superb conditioning, Canas is aware there is one thing he'll never completely outrun. Every time he wins -- and he did it again Sunday, dominating fellow Argentine Juan Monaco in straight sets to advance to the French Open quarterfinals -- the subject of his contested doping suspension is churned in with the sweet cream of victory.
All roads lead back to the case: How well Canas has played since he began competing again last fall after 15 months away; how much he appreciates where he is; how determined he is to clear, or as he says, "clean" his name.
Sunday, the 29-year-old Canas spent at least an hour answering questions in a mild voice, regarding each person in turn with his level brown-eyed gaze. Print media in English. Print media in Spanish. A swarm of radio reporters. A one-on-one television interview. And finally, one more sit-down.
"Sometimes it's hard to every day talk about the same thing," Canas, the 19th seed at his first Grand Slam event in two years, told ESPN.com. "But I knew before I started that this was going to happen. I say the truth, always. For me it's the normal thing. I don't have anything to cover up.
"The way you see me is the way I am now. Before, I was sometimes very nervous or I had a lot of thinking in my head. Now I just try to be simple. I go there and enjoy the moment and try to do my best and try to win. But if it doesn't happen, next week there's gonna be another tournament. There's other things in my life and they're not gonna change for one score."
Even the crisp effort against Monaco wasn't without its reminders of Canas' recent past. When Canas appealed his two-year ATP suspension after testing positive for a diuretic considered a masking agent, Monaco provided written testimony that supported Canas' contention that he was the victim of a prescription mix-up. The two embraced warmly at the net after Sunday's match.
"I didn't tell anybody to lie," Canas said. "I told the guys to tell what happened that day. It was hard to collect the information six months after it happened. Sometimes it's hard to remember the normal day like that."
Monaco, who like Canas was treated for cold symptoms at the early 2005 tournament in Acapulco, Mexico, where Canas tested positive, offered proof that tournament doctors had not kept accurate records of treatment and prescription orders at the event.
That and other new evidence led the Lausanne, Switzerland-based Court of Arbitration for Sport to reduce Canas' suspension to 15 months and order the return of some of his forfeited prize money. Arbitrators deemed that Canas had "no significant fault or negligence" but said they could not absolve him completely.
That is where the matter has stalled for the moment. Canas won an interim and interesting break point in March when the Swiss Federal Tribunal took the unprecedented step of sending the CAS ruling back to the panel. Canas' lawyer Cedric Aguet argued that the suspension violated Swiss law.
"It's simply not acceptable to suspend someone who was the victim of an accidental positive control for a detrimental substance," said Aguet, who has emphasized that a diuretic would have been performance-detracting, not enhancing, in the heat in Mexico.
The CAS panel upheld its own ruling last month in a decision Aguet said was unresponsive to his arguments. Aguet said he has Canas' blessing to press on with an anti-trust complaint before the European Commission citing wrongdoing by the ATP, the World Anti-Doping Agency and CAS.
"Sanctions in doping have to be proportionate to offenses, or it distorts competition," said Aguet, who added that he will not ask for monetary damages in the complaint. "That is for another lawyer. I will not be the one to litigate that. My purpose and Willy's purpose is to bring justice to this process."
So Canas' procedural marathon will continue. It seems at least as fatiguing as the one he logs on the baseline in every match. "You've seen him on the court," Aguet said with admiration. "You have to shoot him to stop him."
Canas will meet No. 4 seed Nikolay Davydenko of Russia in the quarterfinals, but the drumroll has already begun in advance of his potential opponent in the following round: the top-seeded Roger Federer, beaten by Canas twice this year on hard courts.
Some would give Canas a slight edge, both on the surface and under Federer's skin. He was having none of that Sunday and said he would regard the match foremost as a milestone first Slam semifinal.
"If I have a chance to play against Roger in semis, really it's going to be a pleasure to be on the court again with the number one in the world, one of the greatest players in history, and I try to enjoy that," Canas said. "I know I have a chance to win. I know I have more chances to lose.
"But for me, it's one more match in a big stadium full of people, and this one is gonna be great for my career, for my life. I'm gonna try to enjoy every point. The last two were incredible victories and gave me a lot of confidence."
The 35th-ranked Monaco smiled when he was asked to assess the prospective matchup. "Roger has better shots than me, so I think it's going to be easier for Roger," he said. But, Monaco added later in Spanish, "Willy is very hungry and motivated."
Canas can obviously run, and he's not trying to hide. He also seems to have an excellent sense of what he can and can't control. Public opinion -- or locker room opinion, for that matter -- is beyond his considerable range on the court.
"It's an office where we do our job," he said quietly. "Some people you have a good relation with, and some you don't. I don't lose a minute with these people. It's a waste for me."
Hard as he digs for balls in the corners, Canas seems restrained in his reactions these days to good or bad shots, along with his comments.
"I don't know if it gave me more focus in the way I play," he said of his legal travails. "I think the big change I made is that I enjoy a lot to go to the court.
"A lot of people supported me in the bad moment, a lot of people in my country supported me in the bad moment. The only way to say thanks to those people is to go on the court and give my 100 percent. So this, yes, I am focused to do that. It's the only thing I can be sure I'm gonna do."
Bonnie DeSimone is a freelancer who is covering the French Open for ESPN.com.