LAS VEGAS (AP) -- Amanda Nunes stopped Holly Holm late in the first round to defend her bantamweight title, and Jon Jones squeaked out a split-decision victory over Thiago Santos to defend his light heavyweight title at UFC 239 on Saturday night.

Nunes (18-4) remained the pound-for-pound ruler of her sport in her usual devastating style. She floored Holm with a perfectly timed kick to the head, and she mercilessly finished Holm on the ground with 50 seconds left in the first round.

Jones (25-1) had much more trouble with Santos (21-7), who nearly scrapped his way to victory despite injuring his leg early in the fight. Jones fought cautiously and earned a 48-47 decision on two of the three judges' scorecards.