(Reuters) - Spaniard Nicolas Almagro hailed 'sushi power' as he overcame home favorite and defending champion Kei Nishikori in three tight sets in the Japan Open quarter-finals on Friday.
Almagro produced some stunning ground strokes to claim a 7-6(2) 5-7 6-3 victory at the Ariake Colosseum and set up a semi-final clash with Argentine top seed Juan Martin del Potro.
"He (Nishikori) lost set point in the first set and I played really aggressive after that," the Almagro told reporters.
"After that, the match was amazing and I am very happy, because I did a really good job today. It was sushi power."
Sixth seeded Almagro, still an outside bet for a place in the ATP's World Tour Finals in London next month, had trailed by two breaks at 4-1 in the opening set but clawed his way back and prevailed in a tiebreak.
A powerful backhand down the line from Nishikori, who won the title last year to become the first Japanese man to win on the ATP Tour, leveled the match at one set each but an injury hampered his progress in the decider.
The Japanese, ranked 13th in the world, had a medical time out at 2-1 in the third and then lost three straight games from 3-3 as Almagro claimed victory.
"I hurt my back and towards the end and it got to the point that I could not get back (in position) after I hit the ball," Nishikori said. "I'd like to say I did well under the circumstances, but results are what matter.
"I have had problems with my back for the last four or five years. I have hurt it again but it can't be helped. I think I have done well to get this far."
Del Potro needed three sets to overcome awkward Ukrainian Alexandr Dolgopolov 4-6 6-4 6-2 on the Tokyo hard courts.
In the other half of the draw Canadian Milos Raonic beat Slovakia's Lukas Lacko 6-3 6-3 as he tries to follow up his title run at last week's Thailand Open.
He will face Ivan Dodig in the last four after the unseeded Croat downed Jarkko Nieminen of Finland 6-2 7-6(3).
Writing by Patrick Johnston in Singapore