Lambert is prohibited from taking part in practices, games and conditioning, coach Kit Vela announced Friday.
"Liz is a quality student-athlete, but in this instance her actions clearly crossed the line of fair play and good sportsmanship," Vela said.
Video footage of the game shows Lambert, a junior, committing a series of excessively rough plays, including kicking, tackles, a forearm shiver to the back -- in response to an elbow to the ribs -- and yanking BYU forward Kassidy Shumway to the ground by her hair.
Lambert was assessed a yellow card during the 76th minute, apparently for tripping.
On Friday, Lambert apologized for her actions, saying she was "deeply and wholeheartedly regretful."
"I let my emotions get the best of me in a heated situation. I take full responsibility for my actions and accept any punishment felt necessary," Lambert said. "This is in no way indicative of my character or the soccer player that I am. I am sorry to my coaches and teammates for any and all damages I have brought upon them.
"I am especially sorry to BYU and the BYU women's soccer players that were personally affected by my actions. I have the utmost respect for the BYU women's soccer program and its players."
The Mountain West said it endorsed New Mexico's discipline of Lambert, saying her actions violated the conference's sportsmanship policy. The conference said it would continue an internal review of "the overall dynamic involved in the match" and said it would not comment further.
"Liz's conduct on the field against BYU was completely inappropriate," said Paul Krebs, New Mexico's vice president for athletics. "There is no way to defend her actions."
BYU athletic director Tom Holmoe, in a news release, said Krebs had contacted him after the incident.
"It's an unfortunate incident that occurred in the game Thursday afternoon," Holmoe said. "The University of New Mexico and the Mountain West Conference have reviewed the situation and have acted appropriately ... I am pleased with his immediate response to the matter."
New Mexico (13-5-3) was the No. 4 seed in the tournament. Top-seeded BYU (17-2-2), ranked No. 17 in the NCSAA/adidas College Soccer Women's Top 25, advanced to the tournament final against San Diego State with the win.
