“The Tonight Show” host Jimmy Fallon watched his show’s ratings take a hit yet again on Tuesday as competitor “The Late Show With Stephen Colbert” won its fifth straight week in overall viewers — and sources say Fallon’s being forced to change his strategy to win back eyeballs.

“[Fallon] is feeling the pressure. I mean, Stephen Colbert is now beating him in a big way and he has to change his format to keep up because he’s losing viewers,” said a source, adding that Fallon’s getting more political. “They had to figure out a way to get Trump [into his routine] because he’s too weak on Trump, and viewers are going elsewhere. [He’s been] uncomfortable talking about politics, and that’s not what the people want.”

Sources tell Page Six that Fallon was forced to zhoosh up his show and recently debuted a new segment, “This Week in Words,” to rival politically edgy Colbert’s late ratings hike.

A different source added that Fallon “is being pushed to be more political. When he was on ‘SNL’ he could be vicious on the ‘Weekend Update’ desk.”

David Letterman dinged Fallon in New York magazine, saying, “I would have gone to work on Trump.”

CBS crowed Tuesday that former Comedy Central host Colbert won the ratings race for a fifth straight week in overall viewers, growing 29 percent from the same time last year. But a “Tonight Show” source said, “Fallon continues to enjoy a lead over Colbert in the 18 to 49 [demographic], which is more important in the industry than the overall viewership.” They said Colbert’s recent string of wins has gotten slimmer each time.

The numbers still get Fallon’s goat.

“He freaks out over this. He has to be on top,” a source told us.

But another source close to the show insisted Fallon’s a fan of Colbert, and, “We always strive to unveil new sketch material. We have as much fun doing political humor as we do skewering pop culture . . . We love Stephen’s show. They’re doing great stuff. There’s no shortage of material every night.”

An NBC rep commented: “From Jimmy’s first week on the air, the entire team has done a remarkable job keeping ‘The Tonight Show’ fresh and entertaining.”