Donald Trump’s visit to CBS’ The Late Show with Stephen Colbert was the most watched late-night broadcast of Premiere Week. A huuuuuge 4.577 million people caught Trump’s appearance on Colbert’s Tuesday program the week of September 21.

But Carly Fiorina’s visit to NBC’s Tonight Show Starring Jimmy Fallon was tops in the 18-49 demographic most prized by 150921-fiorina-nup_170948_1159_9835a7fa0dab992d941b94a9020c2908.nbcnews-ux-2880-1000advertisers in late night. About 1.5M folks in the age bracket watched Fiorina’s serenading of Fallon on Monday night that week, besting Trump’s 1.3M. Fiorina’s overall crowd clocked in at 4.038 million, making her Tonight Show debut Premiere Week’s second most watched late-night broadcast.

Meanwhile, Shonda Rhimes, creator of (among other programs) ABC’s faux presidential soap Scandal, delivered Jimmy Kimmel’s biggest Premiere Week audience: 3 million viewers, of whom 1.02M were demo viewers.

I want to thank you, not only for being here, but for running for president. I’m not going to say this stuff writes itself, but you certainly do deliver it on time every day,” enthused Colbert, who has been feasting on Trump’s candidacy since debuting as host of Late Show, to Trump in his Premiere Week visit. One night earlier, Fiorina sang a tune she’d composed about her dog on Fallon’s show –  a display of personality considered so daring in political circles it triggered a flurry of press reports comparing it to candidate Bill Clinton’s late-night-TV sax-playing nearly a quarter-century earlier.

Fallon finished first during the first official week of the 2015-16 TV season, in both metrics, though he was down a tick, year to year, as CBS put up much stiffer competition. Colbert gave CBS a big year-to-year boost, scoring Late Show’s biggest numbers in overall audience, and in the demo, since 2011.  The difference between Colbert’s overall premiere-week audience this year and Fallon’s was 364K viewers. Premiere week last year a gulf of 1.2 million separated the two shows.

Same story in the 18-49 demo, where Tonight’s 2014 Premiere Week 1.10/5 rating slipped to this year’s 1.05/5, while Late Show jumped from 14’s 0.46/2 to 0.78/4.

Some of Colbert’s bigger crowd also appears to have come from the Kimmel camp. ABC’s Premiere Week JKL ranked No. 3 in the pack with a 0.59/3, after thumping CBS last year same week with a 0.66/3. Same story in total viewers: Kimmel collared an average ofScreen Shot 2015-09-25 at 8.03.38 AM 2.501 million viewers for the first week of this season and ranked No. 3, compared to last year’s second-place finish with an average of 2.762 million viewers. Kimmel’s Friday show was a repeat; Colbert’s show was delayed on Thursday due to NFL overrun.

Colbert, and Trump, were the news of Premiere Week – aka third week since Colbert’s CBS Late Show debut – but Fallon finished first, despite Colbert and his Trump bump. With the tougher competition coming from the general direction of CBS, NBC notes Fallon ran within 5% of last year’s premiere-week rating in the 18-49 demo (1.05 vs. 1.10).

ABC, meanwhile, noted Kimmel’s Premiere Week performance was his strongest performance in more than 3 months in total viewers (up 15% – 2.501 million vs. 2.178 million) and in the demo 18-49 (26% – 743,000 vs. 592,000).