The late-night ratings battle between Stephen Colbert and Jimmy Fallon really tightened during The Late Show With Stephen Colbert's 13th consecutive win over the once-dominant Tonight Show Starring Jimmy Fallon — and, even more curious, the latter's demo lead grew to its biggest since January.

For the week of April 24, CBS' Late Show averaged 2.74 million viewers. That's a mere 2 percent (just 67,000 viewers) above NBC's Tonight, making for Colbert's narrowest margin of victory since his streak kicked off in January. The gap between Late Show and Tonight has fluctuated greatly since then, with Colbert once averaging as many as 400,000 more viewers than Fallon, but it's rarely been this tight.

Simultaneously, Fallon's latest week saw his biggest victory among adults 18-49 since the start of Colbert's audience streak — one that not-so-coincidentally started with the inauguration of President Donald Trump. Tonight outperformed Late Show by a whopping 50 percent, with the former averaging a 0.66 rating in the key demo to latter's 0.44 rating. The last time Tonight had that much of an advantage was at the top of the year.

But all of Colbert's weekly audience wins have really tightened the gap for the season. For the 2016-17 broadcast season, Tonight is now outpacing Late Show by only an average 63,000 viewers. Closing that gap altogether would be a coup for Colbert in his second year at CBS — and while it's not impossible, it is unlikely.

This all comes as No. 3 Jimmy Kimmel Live! looks ahead to what is typically its best month of the year. A lead-in from the annual NBA Finals, scheduled to begin June 1, generally lifts the ABC late-night show above both of its rivals.