NEW YORK — All that talk about Joanna Jedrzejczyk being the greatest women’s fighter in UFC history? Yeah, let’s put that one on ice for a while.

Rose Namajunas scored a spectacular first-round upset on Saturday at Madison Square Garden, taking apart the now-former champion and stopping her at 3:03 of the first round on the UFC 217 main card at Madison Square Garden.

Namajunas dropped Jedrzejczyk, widely regarded as one of the finest and most technical strikers in the UFC, early with a straight right hand. Jedrzejczyk got up and seemed to recover quickly.

But Namajunas wasn’t done. She caught Jedrzejczyk on the chin with a left hook that dropped her a second time. This time, Jedrzejczyk wasn’t able to survive. Namajunas dropped a series of hammer fists on Jedrzejczyk from the top, forcing referee John McCarthy to stop it at 3:03 of the first.

Jedrzejczyk was aggressive and animated all week and was in Namajunas’ face at the weigh-in and during public appearances. When Jedrzejczyk was shouting at Namajunas during the weigh-in, Namajunas stood quietly and recited The Lord’s Prayer.

“There was a lot of stuff in the press going on and I just wanted to use my gift of martial arts to make the world a better place,” she said.

She made Madison Square Garden a loud and crazy place, as the crowd that seemed to come for the inevitable Jedrzejczyk win got to see one of the biggest title-fight upsets in UFC history.

Jedrzejczyk was attempting to make her sixth consecutive successful defense of her championship, which would have tied ex-bantamweight champion Ronda Rousey’s record for women. But she was never in the fight on Saturday, failing to connect with a serious blow and being dropped twice and finished.

Namajunas, who lost a title shot earlier in her career to Carla Esparza, is a talented and creative fighter whose submissions are outstanding and often jaw-dropping. Few, though, thought she’d be able to stand toe-to-toe with Jedrzejczyk and beat her at her own game.

But Namajunas pulled it off and fulfilled the prophecy of her boyfriend, ex-UFC heavyweight contender Pat Barry, who said that Namajunas would win the title several years ago before she was even in the UFC.

She fought with a calm determination Saturday, beating one of the pound-for-pound best fighters in the world by a wide margin.

It was the first MMA loss for Jedrzejczyk, who entered the bout 14-0 and had talked of moving up to 125 to challenge for the newly created flyweight title sometime next year.

That may yet happen, but the division that she ruled so thoroughly the last several years just took a sudden change of direction.