Mihai Leu also known as Michael Loewe (born February 13, 1969 in Hunedoara) is a Romanian former professional boxer who lived and fought out of Hamburg, Germany. He is the former WBO Welterweight Champion. Leu retired after one title defense, against Michael Carruth, becoming the second European boxer to retire as an undefeated world champion, after Terry Marsh. Due to an injury, he was forced to abandon boxing but, unwilling to give up the world of sports, he turned racecar driver.