UFC Vegas 77: Mayra Bueno Silva submits ex-champion Holly Holm ...

Mayra Bueno Silva has now won four straight including three submissions and a win over a former UFC champion. (Jeff Bottari/Zuffa LLC via Getty Images)

Mayra Bueno Silva faced a big opportunity against former bantamweight champion Holly Holm on Saturday in Las Vegas.

She made the most of it. The 10th-ranked bantamweight contender made quick work of Holm at UFC Vegas 77, securing a second-round submission victory in the main event with a standing guillotine choke.

Holm got a hold on Buena Silva and backed her into the cage just 15 seconds into the round. But Bueno Silva slipped from her grasp and responded with the guillotine chokehold. Holm was not able to escape. She tapped out 38 seconds into the second round, and Bueno Silva picked up the biggest win of her career over the third-ranked fighter in the division.

Bueno Silva was off to strong start Saturday before the submission, with some observers scoring a close first round, 10-9 in her favor.

With the win, Bueno Silva, 31, improves to 11-2-1 in MMA including a 6-2-1 UFC record. The win was her fourth straight in the UFC and her third straight submission. She's now tied with No. 2 Raquel Pennington for the longest active win streak in the division.

For Holm, 41, it marked another tough blow since her 2015 peak defeating Ronda Rousey with a head kick for the bantamweight title in one of the most shocking results in the history of the sport. Holm is 5-7 since that win including a loss to Miesha Tate in her next fight to relinquish the championship. She's 1-2 in her last three fights.