Conor McGregor loses to Nate Diaz at UFC 196, while Miesha Tate defeats Holly Holm

Conor McGregor's momentum was derailed by Nate Diaz

Conor McGregor suffered a humbling submission loss to Nate Diaz at UFC 196 in Las Vegas.

The Irishman was badly hurt by a series of punches from Diaz in the second round and attempted a takedown as a result, but the American finished him off on the ground with a choke.

McGregor, the featherweight champion who voluntarily stepped up 25lbs to make his welterweight debut, now faces a decision regarding his long-term weight division after losing at short-notice to Diaz.

McGregor (right) was damaged on the feet before being finished on the ground

McGregor was clearly at a size disadvantage against the taller and rangier Diaz but likely won the opening round with clever head movement to edge the lion's share of the punching exchanges. His dangerous left fist drew blood from above Diaz's eye, and a series of kicks to the American's lead leg also interrupted his rhythm.

But that range differential suddenly became a bigger issue in the second round. Diaz, whose trademark trash talk had been conspicuous by its absence, found his swagger after buckling McGregor's legs with a straight left hand.

With the Irish fighter quickly becoming a sitting duck, he attempted to take the fight to the ground, but Diaz established a dominant position and forced the submission after 4:12 minutes of the round.

McGregor (right) landed some powerful shots in the first round

"I took the chance," McGregor (19-3) said. "I thought I took the first round, I was inefficient with my energy. I respect Nate, he took the punch. These things happen in MMA. I took a chance and it didn't work out."

Diaz (19-10) added: "If I'm not in the best shape, I've got to start slow, save my energy, and then pick it up."

Earlier, Holly Holm lost her women's bantamweight championship with a submission defeat to Miesha Tate.

Holm, who won the belt in shocking fashion from Ronda Rousey in November, struggled on the two occasions that the fight went to the ground and was put to sleep by a choke in the fifth round.

Tate, who has two defeats to Rousey on her record, almost won the title with a second-round choke but Holm valiantly refused to quit. The defending champion edged the first, third and fourth periods with her more accurate punches and kicks from a standing position but never looked likely to put Tate away.

In the fifth, the challenger dragged her back down to the canvas and sunk in a choke which forced the referee to step in and save Holm.

"I knew I had to finish the fight," said Tate. "I knew I had to be perfect in the fifth round."