Washburn shot 4-of-8 from 3-point range for the fifth-seeded and tournament host Miners (23-9), who will play Southern Miss in the quarterfinals on Thursday. John Bohannon tallied a double-double with 15 points and 11 rebounds, while Vince Hunter and Matt Willms poured in 12 and 11 points, respectively.
Prince Williams, Paris Campbell and Akeem Richmond all scored 14 points as 12th-seeded ECU's (17-16) season came to a close. Caleb White was also a factor with 13 points.
UTEP created some separation in the first half by outshooting ECU from the field, 50 percent to 33.3 percent, as it led comfortably at intermission, 42-26.
The Pirates improved their field goal shooting to 51.6 percent in the second stanza but only managed to bring their deficit to single digits in the final minute.
UTEP overcame a poor free-throw shooting night (12-of-22) by winning both the rebounding (37-30) and turnover (14-11) battles.