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T-Mobile CEO on Sprint: 'Put a fork in it. They're done'

In an interview, outspoken John Legere talks about the suddenly lively Sprint as a competitor, the failed merger with Sprint, and his thoughts on BlackBerry.

John Legere, CEO of T-Mobile, speaks at an Uncarrier event in SF on September 10, 2014. Josh Miller/CNET

SAN FRANCISCO -- Sprint may boast more subscribers than T-Mobile, but John Legere doesn't even regard Sprint as his competition.

In an interview, the outspoken T-Mobile CEO reiterated his goal of surpassing Sprint as the nation's third-largest wireless carrier later this year. "Put a fork in it," he said. "They're done."

T-Mobile has been on a tear, announcing on Wednesday that it added a record gross 2.7 million customers in the month of August -- its best month ever. A mix of Legere's personality, crafty marketing, and a continuous barrage of "Uncarrier" programs have driven the company's momentum. The latest salvo, Uncarrier 7.0, pushes Wi-Fi calling to the forefront, with Apple now supporting the feature.

But T-Mobile isn't the only company on the move. New Sprint CEO Marcelo Claure, who took over last month, has reinvigorated the company with aggressive new offers, including a new iPhone-specific plan that undercuts even its own cheapest rate by $10. Legere applauded Claure for getting into the mix quickly. "You have to give him credit for what he's doing," he said. "He's moving. He's swinging his bat."

Now playing: Watch this: T-Mobile CEO accuses rivals of 'trickery' over iPhone...

But Legere said it was a leap to go from a few Sprint announcements to declaring the company back in the growth period. He warned that Claure has his hands full with a business that could take much longer to turn around.

"It's a totally different situation," he said. "They're trying to get to the point where they want to stop the bleeding. They have a long way to go before their network is competitive."

Sprint's aggressive pricing may end up hurting the company, Legere warned, if customers show up and get a poor experience.

"When your network isn't up to par, you have to compete on price," he said. "If you could, you would do that later. If customers come in because of price and the network's not right, they're going to leave."

Claure said in an interview on Tuesday that the network issue is a concern but added that his customers like the experience, noting that network speeds are high in key markets such as New York.

On Sprint's iPhone-specific plan, which is $50 a month for unlimited data, voice calls, and text messages, Legere called it "trickery," describing the "iPhone for life" plan, which guarantees an iPhone every two years in exchange for $20 a month, as a leasing program where you don't really own the phone (you have to turn in your old iPhone at the end of the two years). He said it was basically a two-year contract.

A Sprint spokeswoman declined to comment.

Legere did offer a little hope for Sprint, noting that he doesn't need Sprint to fail for T-Mobile to succeed. When asked whether both could grow in this market, he said, "of course."

"He's not impacting us, but we're not the enemy," he said. "He wants a fight, well...

"He could kick my ass. He's a big guy."

Up until a month ago, Sprint and T-Mobile were seemingly headed to an inevitable merger, with Sprint parent SoftBank acquiring T-Mobile from parent Deutsche Telekom. The deal was scrapped after the sides realized regulators were dead-set against it.

Throughout this period, T-Mobile was focused on sustaining its momentum, Legere said.

"It was more difficult for [Sprint]," he said. "It seemed like the answer to fix their company was to buy T-Mobile. They had to announce that the answer they were banking on wasn't happening."

Legere declined to speculate on the attempt by French telecommunications company Iliad to buy T-Mobile, saying only, "Anything you hear in the marketplace about T-Mobile is a statement we're doing something right, and they believe there's significant value in our company and our brand."

While the company has a great future as a standalone company, T-Mobile works well with a lot of different players, Legere said. "So stay tuned."

On its larger rivals, Verizon Wireless and AT&T, Legere said he continues to take customers away, with the ratio of customers joining T-Mobile versus leaving to another carrier at more than 2-to-1. In fact, T-Mobile hasn't had one week this year when more people left T-Mobile than joined it.

He said Verizon and AT&T have little reason to change because their businesses are so profitable. He's content with his two rivals sticking with status quo.

"If they're happy, I'm happy," he said. "If they think nothing is going on, have a party."

For his full thoughts on Sprint and the rest of the competition, check out the video at the top.

Legere also touched on the breakup between T-Mobile and BlackBerry. Is reconciliation possible? Watch the video to find out.

Now playing: Watch this: Could BlackBerry and T-Mobile reconcile?

And I played a quick word association game with Legere. Check out his one-word descriptions of his competitors here:

Now playing: Watch this: With one word, T-Mobile CEO John Legere slams his competition

CNET's Shara Tibken contributed to this report.