M47s and M48s were used in tank warfare by the Pakistan Army against the Indian Army's Soviet T-55s, British Centurions and US M4 Sherman tanks in both the Indo-Pakistani War of 1965 as well as the following war in 1971 with at least some good results. During Operation Grand Slam, Pakistani tank forces, composed mainly of M47 and M48 Patton tanks, thrust through the Indian defence-lines very quickly and swiftly defeated back Indian Army armoured counter-attacks. The Pakistanis used approximately a division's worth of tanks in the operation, although not all were Pattons, with upgraded Shermans included as well. In contrast, Pakistan's Patton tank failed to live up to its high expectations in the Battle of Asal Uttar in September 1965, where about 97 Pakistani tanks were lost, the majority of them being Pattons (M47s and M48s). Later, the Patton tank was the main Pakistani tank at the Battle of Chawinda and its performance at that battle was deemed satisfactory against Indian armour.