Eduarda Moura VS Casey O'Neill

Casey O'Neill defeated Eduarda Moura by armbar submission at 3:22 of the first round in their women's flyweight bout at UFC 331 on September 19, 2026. Moura controlled the early exchanges, catching a kick and dragging O'Neill to the mat before establishing half guard and landing ground-and-pound from top position. O'Neill worked back to full guard, and from that seemingly disadvantaged position she elevated Moura, rotated her hips in one seamless motion, and sank a belly-down armbar to force the tap. The finish was an immediate contender for Submission of the Year, showcasing O'Neill's elite positional transitions and finishing instincts.

Casey O'Neill enters on a two-fight win streak — capped by a first-round knockout in March — looking to build a title case in the women's flyweight division against a fellow ranked contender in Eduarda Moura. Moura has a 3-2 UFC record but carries weight concerns after missing the scale three times in her career, including ahead of her last outing. With both women ranked in the top 13 at flyweight, this is a legitimate ranking fight with direct implications for the divisional picture.