It was a new day in the wild 2016 presidential race, and Ted Cruz was ready to seize the moment.

"It is significant that John Kasich is pulling out of Indiana and allowing us to go directly head-to-head with Donald Trump," Cruz said in a radio interview Monday morning as he kicked off a full day of campaigning in the Hoosier State. "I think that is very, very important because the object always has been to nominate the strongest Republican to defeat Hillary Clinton in November."

Hundreds of miles away, surrounded by reporters at a Philadelphia diner, Kasich had a different take. "It's not a big deal," the Ohio governor said.

Such was the awkward first day of the Cruz-Kasich alliance, unveiled Sunday night in a last-ditch effort to deny frontrunner Trump the Republican nomination. Hoping to deny Trump the 1,237 delegates needed to secure the title before the convention, Kasich has conceded Indiana to Cruz, and Cruz has stepped aside for Kasich in New Mexico and Oregon.

The agreement was cheered by anti-Trump forces and denounced by the billionaire, but as the new reality settled in Monday, Cruz and Kasich found themselves grappling with a deal that seemingly created more questions than answers.

Among them: Could the alliance backfire, only fueling Trump's criticism of a "rigged" political system? How much would outside groups, including super PACs supporting Cruz and Kasich, respect the agreement? And how should Cruz and Kasich supporters vote in states where their preferred candidate is now no longer competing?

At first, Kasich said supporters in Indiana still "ought to vote for me." Then his campaign clarified, saying it is not telling Hoosiers who to vote for, only where it is now placing its spending priorities.

Cruz, meanwhile, went Monday without publicly offering guidance to backers in New Mexico and Oregon. The Texas senator, however, did offer an appeal to Kasich's backers in the Hoosier State, which holds its primary a week from Tuesday.

"For the supporters of John Kasich in the state of Indiana, I would ask you to please support our campaign," Cruz said while speaking with reporters in Greenwood, Indiana, comments livestreamed by ABC News. "If you don't want to see Donald Trump as the nominee, if you don't want to see Hillary Clinton as the president ... then I would ask Gov. Kasich's supporters to stand with us, to stand united."

The uncertainty also extended to allies of Cruz and Kasich, whose campaigns had asked outside groups to abide by their agreement. By the end of Monday, the extent to which the main super PACs supporting each candidate would follow through was not entirely clear.

"Of course we will do whatever is best for Gov. Kasich," Connie Wehrkamp, a spokesman for the pro-Kasich New Day for America, said in a one-sentence statement.

Trusted Leadership PAC, the top super PAC backing Cruz, was more detailed, saying it will add a pro-Cruz ad to its $1.3 million buy in Indiana but continue airing an anti-Kasich spot "as we attempt to win every possible vote for Senator Cruz." Trusted Leadership PAC is also shelving plans to advertise in New Mexico and Oregon, according to a statement from Kellyanne Conway, the super PAC's director of research and media outreach.

Another outside group supporting Cruz, the Club for Growth, said it was not planning to make any changes to its $1.5 million effort to boost Cruz in Indiana. Doug Sachtleben, a spokesman for the group, said in an email that Kasich's campaign "is now essentially endorsing CFG Action's ad in IN which says that voters should vote Cruz to stop Trump and a vote for Kasich is a vote for Trump."

Trump, meanwhile, continued to tear into his two rivals, accusing them of cooking up a deal out of desperation. Cruz defended the alliance throughout Monday in Indiana, rejecting Trump's suggestion it represented Washington, D.C., backroom dealing. "It is entirely about the will of the people," Cruz told reporters Monday morning before a rally in Borden.

Whatever the implications of the deal, Cruz's campaign appeared okay Monday with letting another story dominate headlines: Cruz's search for a running mate. Cruz campaign manager Jeff Roe announced on Twitter that the campaign has "narrowed our VP candidates to a short list and are going thru the normal processes associated with picking a running mate."

Among those Cruz is vetting is rival-turned-endorser Carly Fiorina, according to Sarah Isgur Flores, a spokeswoman for Fiorina. The Weekly Standard first reported Fiorina, one of Cruz's most popular surrogates on trail, was going through the process.

"Any responsible candidate, just a couple of months out from the convention, would begin that process," Cruz said in Greenwood, reminding reporters he has previously revealed he is officially looking at potential running mates. "We've begun examining both a long list and now a shorter list that has been culled, and that naturally includes a vetting process.

"At this point," Cruz added, "no decisions have been made in terms of who a nominee would be our the timing of the announcement."

The Washington Post's David Weigel contributed reporting.