Last fall, Phil Mickelson and Jordan Spieth stood at opposite ends of the Ryder Cup spectrum. Mickelson was the second-oldest member of Team USA at 44 (Jim Furyk is a month older) and Spieth was the youngest by three years at 21.

Little did we know, the event would be the start of a budding bromance.

Spieth And Mickelson

After the WGC-Bridgestone Invitational at Firestone Country Club in Akron on Sunday, where Speith finished tied for tenth and Mickelson finished 63rd, Spieth began talking about this weekend's PGA Championship at Whistling Straits. He began describing his planned Tuesday practice round in which he and Justin Thomas were to duel Mickelson and Rickie Fowler. Spieth, who won this year's Masters and U.S. Open and came within one shot of a playoff at the British Open, got downright nasty.

"I'm going to try to get the U.S. Open trophy flown in so I can sit it on the front of each green for Phil so I'll have something for him," Spieth said. "We'll see if we can get somebody to carry it around for the round. It's the first time I have something on him."

Savagery. Just savagery.

Mickelson has five major championships, but none in the U.S. Open where he has a record six runner-up finishes: Payne Stewart's late hold in 1999, Tiger Woods' Bethpage win in 2002, Retief Goosen's second U.S. Open in 2004, Phil's Winged Foot collapse in 2006, another Bethpage second in 2009 and a final-round crumble in 2013 at Merion.

Spieth won at Chambers Bay this year in his fourth U.S. Open try. The Texan, who turned 22 just two weeks ago, showed no mercy in dissing one of the greatest American golfers of all-time.

Of course, Mickelson, a well-documented jokester, responded by reminding Spieth that he has something the kid does not have: A Wanamaker, the PGA Championship trophy.

The Dallas Morning News documented much of the round, noting that Mickelson constantly put pressure on Spieth and Thomas, despite the round being "practice." "Phil's Game" is a common term on tour for the 45-year-old's decision place wagers with younger players on practice days to take his training more seriously.

Spieth is already learning how to fend off Lefty's chirps. He claims the way to get in Mickelson's head is to keep quiet and go unchanged by Mickelson's trash talking.

"[Mickelson] doesn’t like it if you’re quiet," Spieth said Tuesday. "If you give it back to him, that's when he knows [his trash-talking] is bothering you."

Mickelson thought he had an easy dig at world No. 1 Rory McIlroy who ruptured an ankle ligament playing soccer last month. The PGA Championship will be McIlroy's first appearance since the injury.

Spieth, Mickeson and friends played the highest profile practice round match of the week and it did not disappoint. Down two with two to play, Mickelson drained a 15-foot birdie on 17 to tie it. On 18, Fowler knocked in a 35-foot birdie putt, forcing Spieth/Thomas to birdie as well. Spieth's approach shot came to rest five feet from the hole, which set up an easy birdie for the Player of the Year frontrunner.

"I don’t know if I speak for anybody else, but you could feel the nerves at the end of that round," Spieth said. "Because you don’t want to have to hand those guys whatever we play for."

The competitive Mickelson was not happy with the way his round ended, but if there was any more trash talk, it happened off camera. When the round was finished, Mickelson put on his mentor face.

"We have some young guys in the game, like Jordan and Rickie and McIlroy, who are great guys, quality individuals,” Mickelson said. “They treat people well. They represent the game well, as well as having incredible games."

Spieth And Mickelson Red And White

Spieth is a 6-1 favorite to win the PGA Championship, while McIlroy is tied for second at 12-1 odds. Fowler is tied for fifth at 20-1 odds and Mickelson is tied for tenth at 40-1 odds. Tiger Woods is down further at 50-1 odds.

Spieth and McIlroy open the tournament on the tee together, along with British Open champion Zach Johnson, at 2:20 p.m. ET Thursday. Mickelson, who won the tournament in 2005 and finished one shot short of McIlroy last year, tees off at 2:30 p.m. with fellow former champions Jason Dufner and Padraig Harrington.

Woods, the 1999, 2000, 2006 and 2007 PGA champion, tees off at 9:15 a.m. with former champions Martin Kaymer and Keegan Bradley.

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