On 26 March 1959 against
West Indies at Lahore, Mushtaq succeeded his elder brothers
Wazir and
Hanif into Test cricket. Based on his publicised date of birth of 22 November 1943, he was then 15 years and 124 days, the youngest person to play Test cricket at the time. He scored 18 runs in the match and Pakistan were defeated by an innings and 156 runs. The first of his ten Test hundreds would come in his 6th Test, 101 against India in
Feroz Shah Kotla, when he was 17 years and 78 days old, which was the youngest age for a test centurion. The record stood for over 40 years until it was bettered by
Mohammad Ashraful. His next century came against England in 1962 and he would have to wait another 9 years until his next century. In 1970 he played for the
Rest of the World against England in the series that was later stripped of its Test status. Early in 1973, he scored 121 against
Australia at
Sydney and 201 against
New Zealand in his next match a month later. In the latter game, he became the only cricketer other than
Denis Atkinson to score a double century and take five wickets in a
Test match. He finished the year with 777 runs at the average of 86.33. He captained Pakistan in 19 Test matches from 1976–77 to 1978–79. During this time, he scored 121 and 56 and took eight wickets against
West Indies at
Port of Spain in 1976–77 to inflict a rare home defeat on West Indies. Thereby Mushtaq also became only the second player after
Garfield Sobers to score a century and take
five wickets in an innings in a test match on more than one occasion. He led Pakistan to a 2–0 win over
India when the two countries played their first series against each other in eighteen years in 1978–79. He joined
Kerry Packer's
World Series Cricket in the late seventies. He went on to become a coach of
Pakistan Cricket Team and led the side which reached the final of the 1999
Cricket World Cup. ==Minor cricket==