Blake, who knocked off 15th-ranked Juan Martin Del Potro before getting a walkover into the semifinal after David Nalbandian pulled out to injury, hit seven double-faults and generally struggled with his service game throughout.

Nieminen scored three of his five break points in the final set to take it in just over two hours, the 73rd-ranked Finn getting a third chance to pick up his first title at the Royal Tennis Hall. He reached the final here in 2001 and 2006.

Top-seeded Gael Monfils of France faced Milos Raonic of Canada in Saturday's other semifinal.