OMAHA, Neb. >> The rivalry between Michael Phelps and Ryan Lochte goes back more than a decade.

They’ve raced more times than they can remember, always bringing out the best in each other.

Now, they’re getting ready to do it one more time.

In what will be their only real showdown of the U.S. Olympic swimming trials, and likely one of their final races ever, Phelps and Lochte clash again Friday night in the final of the 200-meter individual medley.

Side by side, mano a mano.

“I think it’s one of the greatest rivalries in sports, me and him, just for what we’ve both done in the sport of swimming,” said Lochte, an 11-time Olympic medalist. “He’s the toughest competitor out there.”

Phelps is the most decorated Olympian of them all, the winner of 18 golds and 22 medals overall.

He would certainly rate Lochte among the toughest competitors he’s ever faced.

Never mind that Lochte is battling a groin injury and has yet to qualify for an individual Olympic event at these trials.

“Even if he is hurt, I don’t think he’s going to let anything be an excuse,” Phelps said. “Him and I together have had a pretty decent rivalry back and forth. We’ve been able to really push each other and I would expect that (Friday).”

This one is especially significant for the 31-year-old Lochte, given it’s his only real shot at swimming a race of his own at the Olympics. He injured his groin on the first day of the meet and stunningly finished third in the 400 IM — a race he won at the Olympics four years ago. Lochte followed up with a fourth-place showing in the 200 freestyle, which at least was good enough to put him on the team as a relay swimmer, and he dropped out of the 200 backstroke to concentrate fully on the 200 IM.

He needs to finish in the top two to claim an individual event, but he really wants a win over Phelps before they head to the Olympics.

Lochte was top qualifier in the semis at 1 minute, 56.71 seconds, while Phelps took the second spot in 1:57.61. That means they’ll be right beside each other in the final, just as they’ve been so many times during their dazzling careers.

Lochte has been undergoing extensive treatment and even altered his breaststroke form to help deal with the groin problem.

“I took some painkillers to help me with the pain, just so my mind is off that pain,” he said. “The first part of the breaststroke felt good and then halfway through it started hurting more and more.”

Phelps has already qualified for Rio in the 200 fly, and he’s eager to add two more individual races to his program. He’ll be a big favorite in the 100 fly, a race that Lochte also entered but doesn’t figure to be a major threat.

This is their only fair fight in Omaha.

“Him and I have gone back and forth a number of times in this race,” Phelps said. “During the big meets, we have great races. We’re right there with each other (Friday) in the middle of the pool, probably a couple of tenths apart. We’re going to be out and probably step on the gas a little bit more than we have in the past and you’ll have an exciting race.”

The matchup comes one day after Phelps celebrated his 31st birthday.

His mother rented out a room, allowing friends and family to gather for a low-key celebration.

Then it was time for Phelps to turn his attention to a familiar foe.