Mohinder made his debut against Australia at Chennai in December 1969, as a quick-bowling all rounder. At his peak he was a class top order batsman who mainly played at No. 3 for India. He was also handy with the ball, swinging and cutting the ball with great skill and control. He had a unique run-up where he slowed down as he reached the bowling crease. Behind his seemingly lethargic demeanor were nerves of steel.

Mohinder Amarnath played 69 Tests scoring 4,378 runs at a batting average of 42.50, with 11 hundreds and 24 fifties, and claimed 32 wickets at a bowling average of 55.68 apiece. In 85 One Day Internationals, he scored 1,924 runs at an average of 30.53 and a highest score of 102 n.o. and claimed 46 wickets at 42.84 apiece.

Fiery fast bowlers Imran Khan of Pakistan and Malcolm Marshall of West Indies have praised his batsmanship, courage and ability to endure and master pain. In 1982–83 Mohinder played 11 Test matches against Pakistan (5) and the West Indies (6) and scored over 1000 runs in the two series.

In his book "Idols", Indian legend and compatriot Sunil Gavaskar described Mohinder Amarnath as the finest batsman in the world.

Mohinder made his first test century at Perth at the WACA (the fastest and bounciest wicket in the world) batting against Jeff Thomson at his fastest. He followed this test century with another 10 more against top class fast bowling.

Imran Khan regarded Mohinder so highly that in his book "All Round View" he went on record to say that in the 1982–83 season, Mohinder was quite simply the best batsman in the world. Imran further went on to state that Mohinder should have played non-stop for India right from his debut in 1969 to the time he retired. (After his debut series in 1969, he had to wait until 1975 to make it into the team).

This series saw Imran Khan at his lethal best, supported by the canny Sarfraz Nawaz. In match after match India crumbled against the fiery pace of Pakistan, losing the Second, third and fourth tests 3–0 . Imran Khan who took 40 wickets in the series was jointly awarded "Man of the Series" with Mohinder Amarnath. The catastrophic series for India hastened the end of the career of master batsman Gundappa Viswanath. Mohinder Amarnath was the sole saving grace for the Indian batting line-up for the series as a whole. (An aside – Sunil Gavaskar carried his bat in one innings of the series).

Mohinder Amarnath is best known for his legendary performance in the 1983 Cricket World Cup. He was awarded "Man of the Match" in the finals and semi-finals, playing a star role in leading India to their first ever One Day International title and first World Cup win.

In the semi-finals against England his accurate seam bowling fetched him the top-order wickets of David Gower and Mike Gatting. He gave away only 27 runs in his 12 overs, for an average of a miserly 2.25 an over, the lowest among all Indian bowlers. Returning to bat, he scored 46 runs to give India a solid foundation. He was named the Man of the Match.

In the finals, India batted first