Marco Rubio, on his way to being sworn in as speaker of the Florida House in November 2006, greets Florida Gov. Jeb Bush in Tallahassee. (STEVE CANNON/ASSOCIATED PRESS)

On the night in 2010 that Marco Rubio was elected to the Senate, Jeb Bush stood before a room of jubilant Florida Republicans to introduce a man many saw as the former governor’s protégé. Bush, repeatedly expressing pride in Rubio, was moved nearly to tears. “Marco Rubio makes me cry for joy,” Bush said.

Two years later, Rubio shared his feelings about Bush, describing him in his memoir as “the man I most admired in Florida politics.” Rubio wrote that if Bush had decided to run for the Senate in 2010, “no one would challenge him in the primary — certainly not me.”

But now Rubio is on the verge of doing just that — and on a far bigger stage. In recent days, the senator has increasingly given the impression that he is ready to run for president and, in doing so, redefine his relationship with Bush.

Many in Florida have long seen Rubio as the student and Bush, 19 years his senior, as the teacher. But Rubio, who rose in the state legislature during Bush’s tenure and became House speaker after Bush left office, characterizes things differently — saying he learned by “watching him and working near him.”

“I wouldn’t diminish the relationship or exaggerate it,” Rubio said in an interview this week in Florida.

“It wasn’t that he sat me down and gave me a lecture about it; you learn from being exposed to people,” Rubio added.

[READ: What it’s like to take a political science class with professor Marco Rubio]

If Rubio and Bush go ahead with presidential bids, it would set up a remarkable clash between two men who have not just been political allies for the last 20 years, but who also grew out of the same city, the same political network — even the same Hispanic cultural life of Miami. Bush’s wife is Mexican American, and he speaks fluent Spanish, while Rubio, the son of Cuban immigrants, once called Bush “practically Cuban, just taller.”

As members of the Republican establishment, they would be fighting against each other for the same set of donors, staffers and voters.

Their apparent bond has been an asset to both for years. Bush, the scion of one of the most successful political families in American history, benefited from his image as a mentor to young Hispanic Republicans. For Rubio, an alliance with Bush gave him credibility as a young star trying to make his mark as a statewide, and then national, figure.

Facing each other as rivals, however, could highlight each man’s weaknesses.

Rubio, 43, risks appearing inexperienced standing next to the 62-year-old former two-term governor. Meanwhile, Bush, brother and son to former presidents, could look like the stale, old guard of the GOP in contrast to the freshness of a new generation represented by Rubio.

Bush’s spokeswoman, Kristy Campbell, did not respond to requests to interview the former governor.

[READ: Jeb Bush releases first chapter of e-book]

Some who know both men say that the perception that the two had been such close friends as to never run against each other might always have been more myth than reality.

Brian Ballard, a Tallahassee lobbyist and GOP fundraiser, said Rubio “was in the role of — not necessarily a protégé, but someone who really respected Jeb’s political skill and his intellect and his policy wonkiness.”

Ballard said the relationship was “outstanding,” but, he added, “it’s just that sometimes you compete with your friends.”

Rubio, in the interview, sought to make clear that he did not spend extraordinary amounts of time with Bush. “I never worked for him,” Rubio said. “I was never a staffer of his.”

The strain of Bush vs. Rubio could be felt more by their mutual supporters, some said, than by the candidates themselves.

“I think it would be less awkward for Jeb and Marco than for a lot of us around them,” said Ana Navarro, a Republican strategist from Florida who has been a supporter of both but is siding with Bush in the presidential race.

The two got to know each other when Rubio was working on Bob Dole’s presidential campaign in 1996. Two years later, when the then 26-year-old Rubio was running for local office in West Miami, Bush not only offered him a $50 check for his campaign, he also called him on election night to congratulate him. Two small gestures, sure. But it was clearly a message that Bush thought Rubio was going places.

When Rubio reached a pinnacle of state politics, being voted in 2005 to be next in line for the state House speakership, Bush was there. The ceremony, in which Bush presented Rubio with a symbolic sword, has become shorthand for the passing of the torch from mentor to apprentice.

“I can’t think back to a time when I was prouder to be Republican,” Bush said during the ceremony.

When Republican U.S. Sen. Mel Martinez of Florida announced he would retire early in 2009, one of Rubio’s first moves was to see whether Bush was going to run for the seat. If Bush wanted it, Rubio has said, he wasn’t going to challenge him. But not only did Bush decide against running, he was one of a few who encouraged Rubio to run against Gov. Charlie Crist in the Republican primary.

Crist had been heavily favored and held a wide lead in the polls. But he was viewed with suspicion by many conservatives, and Rubio traveled the state presenting himself as a Bush Republican.

Bush did not initially take sides in the race, at least in public, formally endorsing Rubio in the late stages when it was clear he would win the primary.

“Jeb loved Marco. And let’s just say he didn’t much love Crist,” said Navarro. “He was rooting for Marco every step of the way.”

Navarro said that Bush and Rubio “both recognized it was important for Marco to spread his wings and earn his own stripes and not be seen as Jeb’s Mini-Me.”

When Bush startled the prospective presidential field by moving aggressively in recent weeks to line up donors for a campaign, many Florida backers of the two men assumed Rubio would have to wait his turn. Rubio’s 2010 campaign chair, Florida real estate developer Al Hoffman, told the Tampa Bay Times that “Marco is a great guy and has a tremendous future, but I have to support Jeb first.”

But in recent days, as Rubio has made clear his continued interest in a presidential run of his own, he has signaled his intention to present himself as his own man.

In the interview, Rubio did not dispute the idea that the mentor-protégé relationship had been overblown. “That’s not a knock on him,” Rubio said.

Rubio has also made clear in recent days that he believes there is room in the race for both Bush and him, telling the Des Moines Register in an interview published Thursday that “I have a base of supporters financial and policy-wise that differ [from] Gov. Bush’s.”

Rubio, who will visit Iowa on Friday, also used the Register interview to take a not-so-subtle swipe at Bush: “I think it’s important for this country at this stage in our history to move towards the future. I’m grateful for the service people have given our government and our nation in the past, but I think the time has come for a new generation of leadership in this country.”

Some Florida political experts say the relationship probably was far more practical for both men than personal.

Rick Wilson, a Florida Republican strategist, said that while the two had a good working relationship, “you can certainly see that Marco was plotting his own philosophical course.”

U.S. Rep. Dennis A. Ross (R-Fla.), who served with Rubio in the state legislature, said Rubio seemed to be wary of having to wait longer in the Senate for his next opportunity — and that a Bush candidacy clearly was no deterrent. “One thing I know about Marco: Marco is a little bit impatient,” Ross said.

Dario Moreno, who co-teaches a class with Rubio at Florida International University and has known him since 1999, said Rubio and Bush are “friendly, but they’re not friends.”

“They don’t take hot showers together, but they are political allies and always have been,” Moreno said.

Moreover, Moreno said, it should not be a surprise that two ambitious politicians would consider running against each other when the biggest prize seems within reach.

“Both of them realize that they have a once-in-a-lifetime opportunity,” Moreno said. “How many chances do you really get to be a credible candidate for president?”