Yes, if I read the articles of Wiki and entries at Axisforum, they'll say that it was the British breakthrough at Mareth (by flanking the defensive line) that makes the axis forces in Tunisia collapsed.
Actually, I am thinking that Montgomery displayed his worth here more than what he showed in El Alamein 2. In El Al, the Afrika Korps was like exhausted and popular statistics that I read, showed that Montgomery has superior numbers of guns and tanks and planes compared to Rommel.
Meanwhile in Tunis, the Americans with their Generals (Fredendall and later Patton) practically failed in Sidi Bou Zid, both in defense and counterattack, and then again in Kasserine Pass. They achieved little gain in El Guetter though, but that was after Rommel turned his forces of 10th and 21st Panzer into east, facing the Brits. This is in contrast with Montgomery's maneuver, flanking the Mareth line from the south, and swing then north.