Nadal: I must be humble in comeback

(CNN) -- A new country and a new start -- Rafael Nadal will cautiously embark on his long-awaited comeback tournament in Chile this week.

The tennis star has not played a competitive match since losing in the second round at Wimbledon last June due to knee problems, and he is wary of pushing himself too hard in his first appearance at the Vina del Mar Open.

"I have to take it slowly and be humble to know that things won't be as good as they were before my injury. I need to be patient," the 11-time grand slam champion told reporters.

"I need weeks of working on the circuit. This is my first week and I don't think the goals are the same that the ones I will have in two more months."

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Nadal is hoping to defend his French Open title yet again, aiming for an unprecedented eighth crown in Paris, but the Spaniard's 2013 preparations were ruined by a preseason illness that forced him to miss last month's Australian Open.

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He decided the skip the hard-court event and go straight to his favored clay surface, on which he will also play in a Brazilian tournament after Chile.

"I hope the tournament will help me to get the feeling I need to add week after week after a long period without competition ... results are the least important thing right now," said Nadal, who last week launched a smartphone app that teaches tennis skills.

"If my knee doesn't hurt I have no fear. I've had had more serious injuries in the past and I got stronger after them," he added.

"This is the injury that has sidelined me the longest so maybe it will take me a bit longer to get back my confidence, the good feeling on court, but if my knee doesn't hurt I don't see why I couldn't get back my movements and game style."

The 26-year-old will take to the court on Tuesday for a doubles match, then start his singles campaign the following day after receiving a first-round bye as the top seed in the draw despite slipping to fifth in the world rankings.

Nadal met Chile's president Sebastian Pinera when he arrived on Friday, when he downplayed his chances of a victorious return.

"It was the best decision to come to a country for the first time. Vina del Mar has the surface I need. Losing in the first round is something that could happen, because I haven't played in such a long time," he said.

Meanwhile, the man who last beat Nadal did not need to repeat his Saturday exertions as the Czech Republic reached the quarterfinals of the Davis Cup.

Lukas Rosol had helped the defending champions take a 2-1 lead against Switzerland after a record-breaking seven-hour doubles clash, but his playing partner Tomas Berdych put the tie beyond the home team as he won Sunday's opening doubles rubber against Stanislas Wawrinka.

Berdych triumphed 6-3 6-4 3-6 7-6 (7-5) in more than three hours against Wawrinka, who had beaten Rosol on Friday.

"It was an incredible weekend," Berdych said. "Yesterday was a part of history and today was a really tough one.

"It was a team effort to get ready for the match and I was feeling good from the first point. If I'd lost the fourth set, I would have been able to keep going."

Jiri Vesely stood in for 73rd-ranked Rosol in the dead rubber, but lost to Henri Laaksonen.

The Czechs will next travel to Kazakhstan, who beat Austria 3-1 after returning to the World Group via a playoff following last year's first-round whitewash against Spain.

Kazakhstan defeated the Czechs 3-2 in the country's first top-flight appearance in 2011.

Argentina will host France in another quarterfinal after both nations completed 5-0 victories on Sunday, against Germany and Israel respectively.

Novak Djokovic's Serbia will play either the U.S. or Brazil after beating Belgium 3-2, having lost Sunday's two dead rubbers as the world No. 1 and Viktor Troicki were rested.

Italy edged Croatia 3-2 to earn a clash with Canada, who upset last year's losing finalists Spain to reach the last eight for the first time.

Fabio Fognini won the deciding match for Italy against Ivan Dodig, coming from behind to triumph 4-6 6-4 6-4 6-4.

In Vancouver, Milos Raonic gave Canada an unbeatable 3-1 lead as he defeated Guillermo Garcia-Lopez 6-3 6-4 6-2 to end the hopes of five-time winners Spain -- missing Nadal, David Ferrer, Nicolas Almagro and Fernando Verdasco.

On the women's tour, Mona Barthel won her second WTA title after upsetting top seed Sara Errani in the final of the Paris Open.

The 22-year-old won 7-5 7-6 (7-4) against the 2012 French Open runner-up as she followed up earlier victories over third seed Marion Bartoli and No. 5 Roberta Vinci.

The 45-ranked German denied her more experienced Italian opponent a seventh career title, hitting 53 winners to 16 but making 50 unforced errors to 18.

Russia's Maria Kirilenko won her sixth title by edging German fifth seed Sabine Lisicki 5-7 6-1 7-6 (7-1) at the Pattaya Open, having lost in the final of the Thai event last year.