A pair of former finalists both reached their second career semi-finals at the Japan Open on Friday, with top seed Juan Del Potro struggling to victory while Milos Raonic rolled through.
Del Potro, runner-up five years ago to Tomas Berdych, needed more than two hours to finally overcome stubborn Ukrainian Alexandr Dolgopolov 4-6 6-4 6-2, managing a mere four aces against 11 for his opponent.
Canadian Raonic, seeded third and the finalist a year ago against Japan's Kei Nishikori, was untroubled over barely an hour by Lukas Lacko, hammering the 81st-ranked Slovak 6-3 6-3.
Raonic will next take on unseeded Croatian Ivan Dodig, who beat former semi-finalist Jarkko Nieminen of Finland 6-2 7-6. The possibility of a repeat final for Raonic against home hero Nishikori evaporated though as the fourth seed lost to Spanish number six Nicolas Almagro 7-6 5-7 6-3.
Against Lacko, a loser in his last 14 matches against top 20 opposition, Raonic seized the opening set thanks to a pair of service breaks, winning it in well under half an hour.
The seed took a 2-0 lead in the second and was never challenged, advancing on the first of three match points.
The noted big server finished with just 11 aces but did not face a break point for a second consecutive match.
Del Potro is playing Tokyo for the first time since back-to-back first round defeats at the venue in 2009 and 2010.
The Argentine, who next faces Almagro, is aiming - along with Raonic - to book into next month's eight-man season-ending event in London.
Del Potro stands provisional sixth with this weekend and four more weeks to play in the regular ATP season. Raonic will move to tenth if he reaches the Tokyo final, according to ATP calculations.
Del Potro beat Dolgopolov for the fifth time without a loss in their series, breaking five times in their struggle while losing his own serve on three occasions.
Raonic has a score to settle with Dodig, who has won both of their meetings, including on grass at Eastbourne the week prior to Wimbledon last summer.
"It will be another tough match against Ivan," said Raonic. "I'm focused on what I need to do for the next one. He's playing well, I've been playing well, it should be a great match.
"He's gotten the better of me the last few times, but I feel I've been playing better as the week goes on."
Raonic is on a seven-match win streak in Asia after starting his trip to the Far East by claiming the Bangkok title.
