Roger Federer’s return to action was halted at the first hurdle as 39-year-old Tommy Haas rallied from a set down to beat the Swiss great at the Mercedes Cup.
Federer was at his majestic best to claim the first set but wasted match points as Haas inflicted a second defeat of the season on the 18-time Grand Slam champion, eventually winning 2-6 7-6 6-4 in just under two hours.
The 35-year-old was making his return after a 10-week break during the clay-court swing and he showed little sign of rust in easing to the first set for the loss of just two games.
However, Haas served brilliantly and thrilled his home crowd by closing out his first win over Federer since 2012 and just a fourth in their 17 career meetings.
Haas who has dealt with a string of injury problems over the last few years, is ranked at 309 but playing in tournaments under a protected ranking and he rallied to claim the second via a tie-break.
The German broke to lead 3-2 in the deciding set before fending off a host of break points to consolidate his lead in the very next game, and he then held his nerve to serve out for a 6-4 win.
Federer was back in action after a dominant first half of the season that saw him end a five-year wait for another Grand Slam title when he beat Rafael Nadal in the Melbourne final before claiming the opening Masters titles of the year at Indian Wells and Miami.
Nadal hit back to win a 10th French Open at the weekend and despite his withdrawal from Queens, the renewed rivalry between the pair had gone up a notch ahead of Wimbledon with the pair looking back to their very best.
Next up for Haas is another home favourite Mischa Zverev, who beat German qualifier Yannick Hanfmann 7-6 6-2.
Mischa’s younger brother Alexander returned to action after his shock early exit at the French Open with victory over Adrian Mannarino at the Ricoh Open in s’Hertogenbosch, where Britain’s Aljaz Bedene continued his fine form, beating American 20-year-old Ernesto Escobedo in straight sets.
Bedene, who is seeded eighth, needed just over an hour to seal a 6-3 6-4 triumph that sees him through to a quarter-final with Luxembourg’s Gilles Muller.
Meanwhile, world no 13 David Goffin has withdrawn from Wimbledon having suffered an ankle injury at the French Open.
The Belgian suffered a nasty looking fall when he slipped into the covers at the back of the court during his third round match with Horacio Zeballos and was forced to withdraw.
Goffin had hoped to be fit for Wimbledon which gets underway on July 3 but he took to twitter to confirm his absence from this year’s Championships at the All-England Club.