The rich got richer as the May sweep kicked off Thursday, with every show on the heavyweight lineups at both NBC and CBS improving on their opening-night perfs of a year ago.

The Peacock net won in key demo categories, with the penultimate episode of “Friends” a big ratings draw, but the Eye’s “CSI”-led lineup also was very strong.

According to in-home viewing estimates from Nielsen, “Friends” was the top show of the night in 18-49 (11.2/32, 24.51 million viewers overall), building to its finale this week by posting its best scores since Feb. 12.

Net also led in 18-49 with a 55-minute season finale of “Will & Grace” (10.0/24 in 18-49, 20.53m) and dominated at 10 with “ER” (10.5/27 in 18-49, 22.03m). For “Will,” which featured guest star Jennifer Lopez, it was the best 18-49 result since premiere week and its largest overall aud since November 2002.

Over at CBS, “Survivor” (7.5/21 in 18-49, 20.78m), “CSI” (9.3/23 in 18-49, 26.37m) and “Without a Trace” (5.5/14 in 18-49, 16.70m) all performed well. “CSI” was Thursday’s most-watched program overall and led its hour in adults 25-54 (11.3/25).

NBC took the night over second-place CBS in adults 18-49 (10.2/26 vs. 7.4/19), adults 25-54 (10.7/25 vs. 8.9/21) and even total viewers (21.72m vs. 21.33m). CBS won among men 25-54 (7.6/20 vs. 7.1/18).

Compared to the opening night of the May 2003 sweep, every show on both NBC and CBS was up in adults 18-49: For the Eye, “Survivor” grew by 15%, “CSI” by 3% and “Without a Trace” by 28%; for the Peacock, “Friends” improved by 15%, “Will & Grace” by 8% and “ER” by 4%.

That left the other nets eating their dust, with Fox a distant third in 18-49 with the two-hour season finale of “Tru Calling” (2.0/5) and UPN’s “WWE Smackdown” (1.7/4) topping ABC’s lineup (1.3/3) for fourth.

The Alphabet turned things around the next night, tying NBC for Friday’s preliminary 18-49 Nielsen lead (2.8/10) behind first-place demo showings by “George Lopez” (2.6/10 in 18-49, 6.9m) and “Hope & Faith” (3.1/11 in 18-49, 7.9m). Latter racked up its best numbers in 11 weeks with a seg featuring guest stars Robert Wagner and Tony Curtis.

At 10, the heavily promoted adoption edition of newsmag “20/20” ran second in demos (prelim 2.9/9 in 18-49, 8.8m) to NBC’s “Third Watch” (prelim 3.3/11 in 18-49, 9.6m).

NBC also did well again with a two-hour “Dateline” that finished in virtual first-place ties in both adults 25-54 (3.0/10) and total viewers (8.5m).

CBS, despite third-place demo finishes in 18-49 and 25-54, edged past NBC on the night in total viewers (prelim 8.9 million vs. 8.8 million), getting a boost from a repeat “CSI: Miami” at 10.

Elsewhere, Fox averaged a 2.0/5 in 18-49 and 5.1 million viewers with the network preem of “Lara Croft: Tomb Raider,” and the WB’s opening-hour combo of “Reba” and “What I Like About You” topped their slots among femmes under 35.

On Saturday, Fox led in adults 18-49 (prelim 2.7/10) and was up vs. a year ago with an hour of “Cops” (2.4/9 in 18-49, 6.3m) and “America’s Most Wanted” (2.9/10 in 18-49, 7.9m).

ABC and NBC tied for second in 18-49 (prelim 2.5/9), getting solid returns from repeat movies “Remember the Titans” (2.5/9, 7.3m) and “Twister” (2.3/8, 6.2m) respectively. “Titans” led the 10 o’clock hour in most measures.

Season finale of CBS drama “The District” led the 10 o’clock hour in total viewers (prelim 9.7m) but was third in demos, including a 1.9/6 in 18-49.