Serena Williams (right) is trying to complete the first calendar Grand Slam since Steffi Graf in 1988 by winning the US Open for a 22nd Slam singles crown. (AFP)

AFP/New York

Even with her powerful serve and formidable physical gifts, Serena Williams is getting the most praise from fellow US Open players for her mental toughness and confidence when facing adversity.
World number one Williams is trying to complete the first calendar Grand Slam since Steffi Graf in 1988 by winning the US Open for a 22nd Slam singles crown to match Graf’s Open Era record, two shy of Australian Margaret Court’s all-time record.
“She’s just a beast,” said American Donald Young, who won Saturday to reach the fourth round.  
“I think she turns it on whenever she wants to. It’s tough. It’s a lot of pressure. The way she’s handling it is like a true champion.”
Williams struggled early in her past two matches, even dropping the first set against Bethanie Mattek-Sands before rallying to win the last eight games and advance to Sunday’s fourth-round meeting with US 19th seed Madison Keys.
“Serena is inspiration for everyone who is on the tour, for sure. She’s kind of big champion,” said Czech fifth seed Petra Kvitova.  
“We know how big a fighter she is. We need to be fighters in the tennis world as well. People playing her, they really know that if they win a set it’s not the end. She always lifts her level higher.”
Williams has been pushed to three sets 10 times in 24 Slam matches this year and won them all, eight of them after she dropped the first set.
“I have nothing but admiration for her,” Young said. “She’s just an awesome player. She can come back. She has done it so many times in her career. She has been there. Once you know what it feels like, you can repeat it.”

NO PLAYING DOWN THE SLAM
Three-time defending champion Williams, who holds all four major titles, has tried to downplay the calendar Slam and pump up the “Serena Slam” four in a row already done.
But the buzz of fans, sellout crowds for her matches and talk around Arthur Ashe Stadium says more about how the tennis world regards what Williams is on the verge of achieving.
“I guess in her mind she’s trying to play it down,” said Aussie Samantha Stosur, who beat Williams in the 2011 US Open final—Serena’s most recent loss on the New York hardcourts.
“It’s amazing regardless, whether it stays the way it is or whether she gets the calendar Slam and makes it five in a row. Either way, everybody else has got to admire. I mean, if I was in that position, I’d probably try and play it down too and not think of it as such a huge deal and want it playing on my mind all the time.”
Self belief and confidence is a major part of Serena’s game, said Canada’s Eugenie Bouchard.
“She just has that belief. She knows she’s so good,” Bouchard said.  
“She just fights and finds a way. Even the greatest player of all times loses sets or is down in a match. It just shows all of us we have to fight for every point no matter what. Even if you are the greatest of all time, people are not just going to give it to you.”

‘FREAKING AMAZING’ SLAM
British qualifier Johanna Konta, a fourth-round surprise packet, would enjoy seeing Williams lift the trophy next weekend to finish the calendar Slam—and she’s a big Graf fan.
“That would be freaking amazing,” Konta said. “I admire Steffi Graf because that’s who I grew up watching, but I admire Serena Williams, because, I mean, who doesn’t admire Serena Williams?
“I’d love for her to achieve that. I don’t know really of anyone who wouldn’t. It’s an incredible achievement and one that I can only kind of watch and admire.”
US 13th seed John Isner, into the last 16 with a Saturday win, said Williams has created her own great expectations.
“Most important thing is staying positive out there and just believing. That’s what we’ve seen from Serena,” Isner said. “It’s pretty incredible. She has done it so much that we’ve come to expect it. That’s what makes her a great champion.”