The singer honored the late songstress' memory with an elegant performance of two Selena hits.
Donning an elegant black and silver gown, complete with shimmering diamond jewelry, Brooke performed an emotional rendition of Selena's "I Could Fall In Love," to introduce the evening gown portion of the competition.
Her tribute continued, interspersed throughout the segment, where the former Fifth Harmony singer belted out a beautiful cover of "Dreaming of You."
She was joined by the pageant's Top 10 finalists as she ended the number hitting a high note and smiling for the crowd.
Brooke also opened Sunday's three-hour show with a high-energy performance of her own original single, "No Good."
The 26-year-old performer hit the stage in a white midriff and matching pants and was joined by both back-up dancers and the night's contestants for the big opening number.
Following Brooke's tribute, Selena's sister, Suzette Quintanilla, took to Instagram to praise the performance and Brook for singing her sister's tune.
"Never imagine I would ever ever everrr hear This song sang at a MISS UNIVERSE pageant!" she captioned the clip. "@allybrooke Thank you so much for this! Truly honored you choose this song to honor her."
The emotional performance comes shortly after Brooke honored Selena's memory with a powerful performance of "Dreaming of You," alongside partner Sasha Farber, during Movie Night Week on Dancing With the Stars.
Brooke spoke with ET's Keltie Knight backstage after that episode of DWTS, and opened up about her friendship with the Quintanilla family, and the impact Selena had in her life.
"Well she gave me this, Suzette Quintanilla, which was such an honor, and an emotional moment that [Sasha Farber] was able to experience. He met her too this week," she said while pointing to her Selena hair accessory. "They are so supportive of me and that's the most special feeling in the world because I love their family so much and I love Selena. So it feels pretty unbelievable, honestly."
Check out the video below for more on Brooke's stunning DWTS rumba set to the late singer's beloved tune.
'Dancing With the Stars' Finale: Ally Brooke Earns Perfect Score for Singing and Dancing to 'Proud Mary'