With three days remaining, both NBC and CBS jumped the gun Monday and claimed victory in the May sweeps contest.

The dueling webs had different reasons to crow: NBC will win the month for a seventh-consecutive year in adults 18 to 49, while CBS is on track to bag its first May in total viewers since 1983.

“We clearly had a better May sweeps than anybody else,” said CBS topper Leslie Moonves. “We’re in the best competitive position we’ve been in for many years.”

As the sweeps draw to a close, however, the real story may be ABC’s dramatic year-to-year decline. The Alphabet web is posting double-digit declines across the board and is on track to end May sweeps in fourth place.

Of course, the success last May of the first “Who Wants to Be a Millionaire” celebrity edition gave ABC a major boost. With “Millionaire” down to earth, ABC is down 28% May-to-May in adults 18 to 49 and down 29% in total viewers.

As for the yearlong race, NBC has sewn up the young adults crown, while the total viewers battle is down to a squeaker between CBS and ABC. It might take a Florida judge to call the contest: The Eye is just 24,000 viewers ahead of the Alphabet net.

Nets trade barbs

While there was enough glory to spread around, both networks — speaking to reporters during separate hastily arranged conference calls — couldn’t resist taking a swipe or two at the other guy.

NBC West Coast prexy Scott Sassa went first, pointing out that CBS won just one night in the sweep among adults 18 to 49 and 22 nights throughout the entire season, compared with 13 for the Peacock in May alone.

The net also aired four of the top five shows this sweep among adults 18 to 49.

“We’re relying on more than one show,” Sassa said, referring to CBS’ “Survivor.”

Peacock execs also made a few bold predictions about next season.

“Given our performance in May this season and what we’ll be bringing back, we’re incredibly confident that we’ll win next season,” said NBC Entertainment president Jeff Zucker.

Moonves, meanwhile, noted that the Eye web had made major strides on Thursdays, jumping 215% among adults 18 to 49 since “Survivor” and “CSI” joined the night in February.

“The month of May clearly demonstrated the shift in power (on Thursday nights),” Moonves said.

CBS has also narrowed the median age gap, dropping to its youngest levels since 1996. While Fox (35.9), NBC (45.1) and ABC (46.8) have all started to gray, CBS — while still by far the oldest web — is now down to a median age of 50.9.

“Going into next year our profile should be even younger,” Moonves said.

As for sweeps, CBS showed the most growth of any major net in every measurement. The Eye is up 15% with adults 18 to 49, and may wind up in third place for the month (ahead of ABC).

With three nights to go, NBC leads the adults 18 to 49 race with a 5.0 rating, followed by Fox (4.2), CBS (3.9), ABC (3.8), and a tie between the WB and UPN (1.6).

CBS leads the total viewer sweeps contest with 12.7 million, followed by NBC (12 million), ABC (10.7 million), Fox (8.7 million), UPN (3.8 million) and the WB (3.6 million).

The final season standings are even tighter: While NBC is locked in top place with adults 18 to 49 (4.8 rating), Fox has a razor-thin edge over ABC (4.5 vs. 4.4) for second place. CBS, in fourth with a 4.0, is the closest it has been to first place

Summer plans

Meanwhile, with the season drawing to a close, the nets have turned their attention to summer. NBC execs said they expect to program one-third of their schedule with original programming, including the reality series “Fear Factor” and “Spy TV.”

Peacock also has the half-hour sketch comedy “The Downer Channel” and the leftover sitcoms “Kristin” and “Go Fish.”

Reality show “Lost” will premiere in September, while the net will air original “Weakest Link” segs at 9 p.m. Mondays and repeats at 10 p.m. Sundays.

CBS airs “Big Brother” three times a week this summer in addition to its regular dose of newsmagazines.

“Two years ago nobody had even heard (of summer originals),” Moonves said. “Clearly, it can be helpful if you have the right programming.”

(Rick Kissell contributed to this report.)