NBC can only hope U.S. swimmer Michael Phelps keeps his world-class form when the actual Olympics roll around.

Phelps set a world record last night in the men’s 400-meter individual medley, and it helped NBC’s coverage of the U.S. Olympic swimming trials average a 2.0 rating at 8 p.m. among viewers 18-49, good for No. 1 in the hour.

NBC had two hours of Olympic trial coverage, led by track and field at 7 p.m.

Over the entire two hours, the network averaged a 1.6, but with a steady growth in viewership, rising 91 percent from the first half hour (1.1) to the last (2.1).

Track and field and swimming, however, weren’t as popular as the network’s gymnastics coverage the prior Sunday.

NBC posted a 1.2 at 7 p.m. last night, down 29 percent from the 1.7 it posted in the same hour last week. The 8 p.m. hour's 2.0 rating was down 9 percent from a 2.2 the week before.

Still, NBC was first for the night in 18-49s with a 1.9 average overnight rating and a 6 share.

ABC was second at 1.6/5, Fox third at 1.5/5, CBS fourth at 1.4/4, Univision fifth at 0.8/2 and CW sixth at 0.3/1.

ABC began the night in the lead with a 1.7 at 7 p.m. for a repeat of “Wipeout,” followed by CBS with a 1.4 for “60 Minutes.” NBC and Fox tied for third that hour at 1.2, NBC for Olympic track and field trials and Fox for the first hour of the movie “Lost World: Jurassic Park,” with Univision fifth with a 0.7 for “Hora Pico” and “Familia P. Luche” and CW sixth with a 0.3 for a repeat of “One Tree Hill.”

At 8 p.m. NBC took the lead with a 2.0 for Olympic swimming trials, with CBS second with a 1.7 for “Million Dollar Password.”

ABC and Fox tied for third at 1.6, ABC for a repeat of “Extreme Makeover: Home Edition” and Fox for more “Jurassic Park,” with Univision fifth with a 0.6 for “Querida Enemiga” and CW sixth with a 0.3 for repeats of “Everybody hates Chris” and “Aliens in America.”

ABC regained first place at 9 p.m. with a 2.1 for another “Home Edition” rerun, while NBC and Fox tied for second at 1.9, NBC for its first hour of “Dateline” and Fox for the last hour of “Jurassic Park.”

CBS was fourth with a 1.4 for a repeat of “Cold Case,” Univision fifth with a 0.8 for “La Rosa de Guadalupe” and CW sixth with a 0.3 for repeats of “The Game” and “Girlfriends.”

At 10 p.m. NBC led with a 2.4 for the second hour of “Dateline,” followed by CBS with a 1.3 for another “Cold Case” rerun. ABC was third with a 1.0 for a repeat of “Desperate Housewives” and Univision fourth with a 0.9 for “El Pantera.”

Among households, CBS was first for the night with a 5.2 average overnight rating and a 9 share. NBC was second at 4.1/7, ABC third at 3.0/5, Fox fourth at 2.4/4, Univision fifth at 0.9/2 and CW sixth at 0.6/1.