Day and Fowler target Rory

Jason Day and Rickie Fowler are determined to keep the pressure on leader Rory McIlroy going into the third round of the USPGA Championships.

McIlroy has maintained his recent outstanding form and leads by one stroke going into day three at Valhalla.

Australian Day fired Friday's best round, a six-under 65, to stand behind McIlroy and Fowler is a further shot adrift after a 66, setting up what could be a showdown of young stars for the Wanamaker Trophy.

"Rory is obviously on top of his game right now," Fowler said. "He has been driving the ball very well. When he does that it kind of alleviates any stress from anywhere else and he's able to go full throttle and not really let up."

Day has five top-four finishes in majors including runner-up showings at the 2011 Masters and US Open and 2013 US Open - but has yet to hoist a major trophy.

"I've been close a lot of times. I just have to keep knocking on the door and hopefully it will fall my way one day - or just knock the door down and take it," Day said.

Day, a year older than McIlroy and Fowler at 26, has learned a key lesson from past failures.

"Just not to be scared about winning," Day said. "It's hard to win. Some people can handle it. Others can't. It's OK to feel uncomfortable and sometimes you feel like you want to run away. Sometimes you feel a little bit better where you can go on and fight.

"I've just got to go out there and just embrace being uncomfortable again, really play my game and not really think about anyone else."

McIlroy, who played alongside Fowler in the final group at Hoylake on his way to lifting the Claret Jug, ran out to a big lead and held on down the stretch. Day will play alongside him on Saturday and try to make sure that does not happen again.

"I'm clearly not the favourite with how Rory is playing," Day said. "He has been playing great. He looks confident. He's hitting the ball longer and straighter than pretty much everyone in the field.

"It's going to be tough to beat him. But then again, there are a lot of great golfers behind us that are in form. Obviously McIlroy, with how he's playing, he could run away with things again, so I'm going to hopefully try and keep pace.\"

Fowler, a runner-up at the British and US Opens who shared fifth at the Masters, could be the first player since Tiger Woods in 2005 to post top-five finishes in all four majors in a single year.

"Rory has been playing very well and it has been fun to play with him a bit," Fowler said. "He's the best player in the world right now. I would say a lot of that is his confidence with the way he is driving the ball.

"So we will see if he and I can go put out some good rounds. Maybe we can be in the final group on Sunday. You never know.

"The Open definitely wasn't the last final group in a major that him and I will be a part of. Maybe we will get another one for Sunday."

Fowler says his game has grown even if he has not managed to win a major yet.

"I'm very pleased with where my game is at and with the three finishes I've had in the majors this year," he said. "It feels like I have gotten better at each one and I have felt more and more comfortable every time."

And he looks forward to a long rivalry and friendship with McIlroy.

"I look forward to growing the friendship and also the rivalry between us," Fowler said. "It's going to be fun to be able to do stuff together but also try to beat up on each ot her at the same time."

Watch live coverage of the third round of the US PGA Championship at Valhalla from 4pm on Sky Sports 4 on Saturday.