Jeff Haynes / Reuters

Michael Phelps and Ryan Lochte have each won a head-to-head race this week. Now they'll be out to one-up the other in the final of the 200-meter individual medley on Saturday night.

By BETH HARRIS

updated 1:24 p.m. ET June 30, 2012

OMAHA, Neb. - Ryan Lochte and Michael Phelps offer up a tantalizing glimpse of what awaits at the Olympics when they swim side-by-side one last time at the U.S. trials.

The rivals have each won a head-to-head race this week. Now they'll be out to one-up the other in the final of the 200-meter individual medley on Saturday night.

It will be a busy night for Lochte. He will swim the 200 backstroke final first, and less than a half-hour later he'll dive back into the water to take on Phelps in the 200 IM final.

"I'm up for that challenge," Lochte said. "It's something I've been doing for four years now, challenging myself. I'm definitely ready."

So is Phelps.

"Obviously, I want every race," said Phelps, who turns 27 on Saturday. "Hopefully, I'll get a birthday present."

He wraps up the night with the 100 butterfly semifinals.

In the 200 IM semifinals on Thursday night, Lochte and Phelps raced next to each other. Lochte was the top qualifier with the fastest time in the world this year (1:55.51), while Phelps finished about a body length behind (1:56.66).

"I knew he kind of took off, so I was like I probably should save something for tomorrow," Phelps said. "I kind of shut it down once the race was kind of over."

Earlier, Lochte cruised through the semis of the 200 back with the fastest time of 1:55.73. Tyler Clary was next (1:55.88) in what appears to be a two-man race. Only one other qualifier for the final was within 3 seconds of the leaders.

The women have two finals on Saturday night, with the chances dwindling for some big names.

Natalie Coughlin has her last realistic shot to make a third Olympic team and take a shot at tying Jenny Thompson and Dara Torres as the most decorated female Olympians in U.S. history.

Coughlin won six medals in Beijing and she has 11 overall, one shy of Thompson and Torres. But there may not be a chance to tie them in London.

Having already missed out in the 100 butterfly and 100 backstroke, Coughlin goes in the 100 freestyle. She barely got out of the semifinals Thursday night, finishing seventh overall to snag one of the last spots for the final. Amanda Weir was the fastest qualifier in 54.14, followed by Missy Franklin (54.19) and Allison Schmitt (54.23).

With a loaded final that also included Dana Vollmer and Jessica Hardy, Coughlin looks like a longshot for an individual berth in London. She'll need to finish in the top six of the eight-woman final to earn consideration for the 400 free relay team.

"If I don't, I don't," Coughlin said. "Life will go on. That's why you don't see me freaking out."

Rebecca Soni is the overwhelming favorite in the 200 breaststroke and looking to make up for her upset loss in the 100 breast. She qualified first in 2:21.45, the fastest time in the world this year.

"It's close to my best," she said.

Amanda Beard, trying to make her fifth Olympic team at 30, also advanced to the final, as did Breeja Larson, the Texas A&M sophomore who won the 100 breast over Soni.

Janet Evans' comeback is expected to end in the 800 freestyle. The 40-year-old mother of two has already conceded that she won't be going to another Olympics as part of her comeback attempt after 15 years in retirement.

Two-time Olympian Katie Hoff could bid farewell, too. She is entered in the 800 free prelims, but she had said she was going to leave it to her coach to decide whether she would swim the grueling event after failing to make the 400 free final.