Amanda Nunes 'Just Checked Out' in Submission Loss to Julianna Pena at UFC 269

Amanda Nunes' reign of dominance as UFC women's bantamweight champion came to a stunning end Saturday night at UFC 269 when she was submitted with a rear-naked choke by Julianna Pena in the second round. 

Speaking to Joe Rogan inside the octagon after the bout (starts at 40-second mark), Nunes explained she "just checked out" when Pena was able to submit her. 

Nunes has been arguably the most dominant champion in UFC for the past five years. She won the title from Miesha Tate at UFC 200 in July 2016. 

Starting with that bout, Nunes had won nine consecutive title fights. Six of those victories came via stoppage by TKO or submission. She held the women's bantamweight and featherweight titles simultaneously for three years. 

Overall, Nunes had won 12 consecutive bouts. Her last loss prior to UFC 269 was against Cat Zingano at UFC 178 in September 2014. 

Ronda Rousey's final UFC bout to date was a first-round TKO at the hands of Nunes at UFC 207 in December 2016. 

Per Timothy Finnegan of DKNation.com, Nunes listed as a -1000 favorite (bet $1000 to win $100) to retain the bantamweight crown against Pena by DraftKings. 

Nunes still holds the featherweight championship. She most recently defended the 145-pound title against Megan Anderson in March. 

The Brazilian superstar is one of four fighters in UFC history to hold two titles simultaneously. Conor McGregor (men's featherweight, lightweight), Daniel Cormier (heavyweight, light-heavyweight) and Henry Cejudo (bantamweight, flyweight) previously accomplished the feat. 

Pena was just 2-2 in her previous four fights before Saturday's pay-per-view. She had never been in a championship match until squaring off with Nunes.