Stuttgart - Roger Federer said on Monday his motivation is sky-high as he bids for a possible return to the number one ranking if he reaches the final at the Stuttgart Cup.
The 36-year-old Swiss, second in the ATP standings behind 11-time French Open champion Rafael Nadal, has it all to play for this week at the hilltop Weissenhof club, where he lost a year ago in the first round to longtime friend and rival Tommy Haas.
After sitting out the clay season to fully rest and prepare for the grass and last playing match in Miami on March 24, the 20-time grand slam winner is quietly confident that all is falling into place as he mounts his quest for a ninth Wimbledon trophy next month.
"There are a lot of things at stake," the Swiss, who enjoys a first round bye, said. "I expected Rafa to win the French - not taking anything away from him.
"But that creates a situation I was expecting. I know I have to reach the final here to get back to No. 1, that's an extra motivation.
"But I'm taking one thing at a time and not looking too far ahead. Margins on the grass are slim, it's not so simple to win a Grand Slam, it's seven matches -- that's a lot of tennis."
Federer is beginning his grass season in Stuttgart for the third consecutive year after reaching the 2016 semi-finals where he lost to Dominic Thiem.
The icon of the sport leads the field, with Frenchman Lucas Pouille second and his opening opponent was determined in the first match of the week as German Rudolf Molleker beat compatriot Jan-Lennard Struff 6-4, 6-7 (5/7), 6-3.
Tomas Berdych is seeded third, ahead of Australian Nick Kyrgios, making a return to singles after elbow problems which have kept him off court since mid-April.
Federer attempted to calm weekend speculation that he is about to sign a lucrative clothing contract with Japan's Uniqlo after his 10-year pact with Nike expired three months ago.
The Swiss said it's all still in the air and his management is dealing with several options in the negotiations, worth a reported $300-million from Uniqlo for a decade and extending into his eventual retirement.
"It's rumours, I haven't had a Nike contract since March when it ran out. We're talking, we will see what happens.
"It's all part of the game I guess, an unfortunate part. This is an opportunity to see what's going on. I'll let you know, we'll see."