New Jersey Gov. Chris Christie endorsed Donald Trump in Texas today just ahead of Super Tuesday — and immediately took shots at Sen. Marco Rubio, who tore into the billionaire during last night’s GOP debate.

“I find it fascinating that someone who barely shows up for work in the six years he’s a United States senator is going to talk about someone else being unprepared,” Christie said during a press conference with Trump this afternoon. “The fact of the matter is Sen. Rubio has shown himself … to be unwholly prepared to be president of the United States.”

Christie said he’s available to help Trump throughout the campaign, in a sign that Trump may use him as an attack dog — particularly against Rubio — in the weeks ahead. Christie and Rubio frequently mixed it up on the debate stage, and the New Jersey governor was credited with knocking Rubio off his game during a debate in New Hampshire earlier this month.

“I thought he was gonna die,” Trump recalled today, turning to Christie and adding, “Good job, Chris.”

But Christie’s own campaign never got off the ground — despite a late endorsement by popular moderate Massachusetts Republican Gov. Charlie Baker — and he dropped out of the 2016 race days later, after a dismal finish in the Granite State primary.

Christie said after dropping out, he “took a deep breath,” met with his family and discussed whether he still wanted to play a role in the campaign.

“We want to be with the person that we thought will provide the strongest leadership for American and the person who could best make sure that Hillary Clinton never gets within 10 miles of the White House,” he said. “We made the decision that the only clear choice was Donald Trump, the best choice was Donald Trump.”

Eleven states will award 595 delegates on Super Tuesday, the biggest nominating contest of the campaign.

During today’s press conference, Trump dwelled on Rubio and his poor New Hampshire debate performance weeks ago.

“Once a choker, always a choker,” said Trump. “It never ever changes. The guy who misses the kick misses the kick. … That was one of the epic meltdowns. He didn’t know where he was.”

He also called Rubio — widely touted as having landed key punches on Trump during last night’s GOP debate — “a lightweight.”