Jay Leno’s last episode as host of “The Tonight Show” (we think) has scored the program’s most-watched episode in more than 15 years.

In updated estimates for Thursday night, Nielsen said “Tonight” drew a big 14.64 million viewers overall, the fourth biggest ever for the show. The only shows to rate higher were May 20, 1993 (“Cheers” finale, 22.4 million), May 25, 1992 (Leno’s debut, 16.1 million), May 14, 1998 (“Seinfeld” finale, 15.0 million) and Feb. 6, 2014 (Leno’s final telecast, 14.6 million).

The final “Tonight Show with Jay Leno” was up 283%, nearly tripling the show’s season average in total viewers (3.82 million heading into this week). And in adults 18-49, “Tonight” did a 3.8 rating — more than four times the show’s average this season (0.9) and its highest since Conan O’Brien’s final night as host in January 2010.

Leno got a nice assist on Thursday night from NBC’s special early coverage of the Winter Olympics in advance of Friday’s Opening Ceremonies. The Peacock averaged a 6.0 rating in adults 18-49 and 20 million viewers overall in primetime, the largest aud for any network on the night since the opening game of the NFL season last September.

“Tonight Show” had certainly been picking up ratings steam heading into this week, as it averaged a nightly audience of 4.99 million viewers for the Jan. 27-31 frame — up about 30% from the comparable week a year ago — and crushed its ABC and CBS competition. CBS’ “Late Show With David Letterman,” which aired a few repeats during the week, averaged about 3 million, and ABC’s “Jimmy Kimmel Live” drew about 2.4 million.

The last time Leno drew more viewers in a week was March 1-5, 2010 — his first week back for his second stint in the host’s chair of “The Tonight Show.”

Through 19 weeks, “Tonight” was enjoying its most-watched season in five years. And Leno exits “Tonight” on a 67-week winning streak in total viewers against rival Letterman’s CBS show.

“Late Night with Jimmy Fallon” followed Leno on Thursday with 6.01 million viewers, its largest since a special post-Super Bowl Sunday episode in February 2012.

Leno’s final episode did not start off with a sentimental vibe, our Brian Lowry wrote in his review, but went in that direction as the night went on.