LOUISVILLE, Ky. - Phil Mickelson pointed his putter toward the cup, took a step and punched his fist to celebrate a clutch birdie. Boo Weekley revved up the crowd after holing a 50-foot putt from just off the green. Anthony Kim set a record for high-fives.

Yes, those were the Americans having all the fun Friday at Valhalla.

At the Ryder Cup, no less.

“My cheeks are sore from smiling all day long,” Justin Leonard said. “This was a lot different than my other Ryder Cup experiences.”

In a stunning turnaround, the Americans rallied from a back-nine deficit four times to take a 5½-2½ lead, their largest margin after the opening day since continental Europe first was included in the Ryder Cup in 1979.

Mickelson and Kim twice came back from three-hole deficits and picked up 1½ points, as many as Lefty earned in the last two Ryder Cups combined. Leonard had never won a match in any Ryder Cup until two blowout victories with Hunter Mahan, one of six U.S. rookies who played like recent European dominance really was ancient history.

“We’re in a good place,” U.S. captain Paul Azinger said. “Who would have thought?”

The Americans hadn’t led after any session since last winning the Ryder Cup in the “Miracle at Brookline” in 1999. But with six rookies and no Tiger Woods, they lost only one of eight matches and left European captain Nick Faldo wringing his hands.

Europe has won the last three Ryder Cups — and five of the last six — but now finds itself desperate to catch up.

“We’ve had a tough time,” Faldo said. “We lost a few points, but we haven’t lost any spirit.”

One of the few bright spots for Europe was Lee Westwood, who tied Arnold Palmer by running his unbeaten streak in the Ryder Cup to 12 matches. Westwood and Soren Hansen birdied the last three holes in the final fourballs match of the afternoon, the last one enough to earn a halve against Weekley and big-hitting J.B. Holmes.

“It’s a novelty, isn’t it?” Westwood said. “It’s not the position we wanted to be in, that’s for sure.”

Westwood landed in an even worse spot after the long day. In a surprising move, Faldo decided to bench Westwood and Sergio Garcia for the Saturday morning foursomes. Neither has ever missed a Ryder Cup match — 27 straight for Westwood, 22 straight for Garcia. Combined, they have a 27-5-8 record in team play.

Rarely has a European captain shook up his lineup so drastically. But then, rarely is Europe behind.

Slide show   Clash of continents Images from the Ryder Cup between the U.S. and European teams. more photos

Azinger will send out the same players for the Saturday morning foursomes that he used on the opening day, which produced a 3-1 lead. It was the first time the United States won the first session of the Ryder Cup since 1991.

Even so, Captain America was cautious.

“We’ve got a long, long way to go,” he said. “And we know how good they are.”

Even so, it was an amazing start for the Americans.

In the opening match, Mickelson and Kim trailed by three holes with six to play until winning three straight holes and earning a halve against Padraig Harrington and Robert Karlsson. Down by three after four holes in the afternoon, Kim gave them their first lead of the day with a 7-foot birdie on the 14th, and Mickelson dropped in a 20-foot birdie on the 17th that led to a 2-up victory.

“We played with a lot of heart and a lot of emotion today to pull the halve and win out,” Mickelson said. “We have a lot of work to do. This is a fun day. I love playing with this guy. Anthony has got this youthfulness to him, and he has a lot of game.”

It was a big day for most of the U.S. rookies, who went 3-2-2.