New York - Serena Williams is steaming at full speed toward a sixth US Open triumph, but Caroline Wozniacki isn't conceding anything in her quest for a first Grand Slam crown.
The two friends meet Sunday in the championship match of the last Grand Slam of the year.
World number one Williams is vying to become the first woman to win three straight titles at Flushing Meadows since Chris Evert won four on the trot in the 1970s.
With a win she'll join Evert and Martina Navratilova on 18 career Grand Slam titles - a pursuit that has been stalled as she failed to make it past the fourth round in any other major this year.
Her third-round singles exit at Wimbledon was followed by a bizarre departure from doubles, Williams looking weak and woozy before sister and playing partner Venus led her from the court mid-match.
Following on from her second-round French Open exit, it sparked immediate speculation not only as to the state of her game but also her psyche.
"There's always skeptics," said Williams, who says she was suffering from a virus in London. "I worked really hard for Wimbledon. I was disappointed and sad - and shocked - that I wasn't able to win.
"I worked hours, more than I worked before. Maybe it's just paying off now."
Maybe it is.
Williams hasn't dropped a set en route to the final, dispatching 17th-seeded semi-final opponent Ekaterina Makarova 6-1, 6-3 in an hour in her latest show of strength.
She's a prohibitive favourite over Wozniacki, far removed from her days at number one back in 2010 and back in a Grand Slam final for the first time since her 2009 US Open runner-up finish to Kim Clijsters.
That's fine with Wozniacki.
"I always believe in myself when I go out to play," Wozniacki said after securing her finals berth when China's Peng Shuai dramatically retired with heat illness while trailing in their semi-final.
"I definitely believe that no matter who stands on the other side of the net I can win the match."
Williams has won eight of their nine encounters, but Wozniacki is encouraged that in recent meetings in Montreal and Cincinnati she pushed her good friend to three sets.
"When she's on fire, she's hard to beat," Wozniacki said. "But I have had two tough matches against her the last few weeks. I was really close. Hopefully for me that would be third time's the charm.
"It's going to be exciting."
Williams is expecting another close match.
"She knows my game well and she knows how to play," Williams said. "She's so consistent, that's one of the things that makes her really tough."
The key in the face of that Wozniacki persistence, Williams said, "Just stay calm, just be able to relax and be happy."
Wozniacki - who toppled five-time Grand Slam winner Maria Sharapova in the fourth round - believes she'll benefit from the experience of her first US Open final, when she was 19.
"I didn't know what to expect from my nerves," she said of that match against Clijsters. "She had been out there before. So this time it's going to be different.
"I have definitely learned a lot in those years. I have learned more about myself," said Wozniacki, who has come on strong this season since the painful and public end of her engagement to star golfer Rory McIlroy.
"It would mean so much to me," added Wozniacki, once knocked as a number one who hadn't won a major.
"It would definitely have the media stop talking about my lack of a Grand Slam, so that would be nice."
Results on Friday from the 12th day of the US Open, the final Grand Slam tournament of 2014 (x denotes seeded player):
Serena Williams (USA x1) bt Ekaterina Makarova (RUS x17) 6-1, 6-3
Caroline Wozniacki (DEN x10) bt Peng Shuai (CHN) 7-6 (7/1), 4-3 - retired
Sania Mirza/Bruno Soares (IND/BRA x1) bt Abigail Spears/Santiago Gonzalez (USA/MEX) 6-1, 2-6, 11-9