CNN
Tapper began an interview on the network by telling Rubio it was "not a good night" for him, as Trump was on track to win as many as eight states while Rubio walked away with just one victory.
"Is it possible that your quarrel is not so much with Donald Trump as it is with Republican-primary voters?" Tapper asked Rubio.
Rubio told Tapper he was "mis-analyzing the map," arguing that his campaign over-performed expectations in Virginia, where he suffered a relatively narrow defeat to Trump. Rubio also eventually took home a victory in Minnesota.
He also took jabs at rival Ted Cruz, the senator from Texas. Cruz won the states of Oklahoma and Texas on Tuesday - but Rubio said a map that included many Southern states was supposed to serve as Cruz's "firewall." He argued that the upcoming primary schedule, which will feature his home state of Florida, would serve as a boon for his campaign.
Rubio said his ramped-up attacks against Trump were taking their toll, but Tapper didn't buy it.
"Senator, you keep saying that, and he keeps winning states," Tapper said. "You're talking about Virginia, and that's another state Donald Trump won. And I'm just wondering if there's a certain amount of denial that you're in this race."
Rubio shook his head, again pointing ahead to upcoming states he said were more favorable to his candidacy. He also said the 2016 Republican presidential primary was anything but standard.
"Usually at this point in the race, you'd have a frontrunner, and other people would be saying, 'You need to drop out and rally around the frontrunner for the sake of the party,'" Rubio said. "They're saying the opposite now. There will never come a time in this race where our supporters are asking us to get out and rally around Donald Trump."
He added that if the party went on to nominate Trump, it would be the "end of the modern Republican Party."
Watch part of Rubio's interview below:
.@marcorubio: @tedcruz "was supposed to have that Southern firewall. It didn't happen" https://t.co/ud3Wy2I4r0 https://t.co/ByyrsY2Xlu
- CNN Politics (@CNNPolitics) March 2, 2016