Novak Djokovic defeated Feliciano Lopez in four sets in a match that dipped into Wednesday morning to advance to the U.S. Open semifinals for a ninth consecutive year.
The world's top-ranked player had played Lopez just once since winning in Flushing Meadows in 2011, and narrowly avoided being taken the distance in a 6-1, 3-6, 6-3, 7-6 (7-2) triumph at Arthur Ashe Stadium.
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Djokovic's victory sets up a blockbuster with defending tournament champion Marin Cilic, who also advanced on Tuesday in a marathon 6-4, 6-4, 3-6, 6-7 (3-7), 6-4 victory over Jo-Wilfried Tsonga.
Cilic has not beaten Djokovic in their 13 career meetings.
The Croatian, who hurt his right ankle in his fourth-round win over Jeremy Chardy over the weekend, said he was initially worried post-match Tuesday, but the pain subsided.
"The ankle is doing OK. I was a bit scared after the match with Chardy, but it's all right," he said. "It's great to have also two more days until semis, actually three days."