[8][9] Krishnan qualified for 1953 Wimbledon and reached final of Boys' singles title losing to Billy Knight.

In 1959, Krishnan won the Queen's Club Championships title, defeating both Alex Olmedo and Neale Fraser in the final two rounds.

Krishnan won the 1959 U.S. Hard Court Championships in Denver with wins over Gardnar Mulloy in the semifinal and Whitney Reed in three straight sets in the final.

[4] These performances gained Krishnan seventh seeded status at Wimbledon in 1960, where he reached the semi-finals losing to the eventual champion Fraser.

In 1961, Krishnan again reached the Wimbledon semi-finals by beating Emerson in straight sets in the quarter-finals but lost in the semis to eventual champion Laver.

[18] Krishnan won the 1963 Antwerp International Championships tournament on red clay with a four-set win in the final over Nicola Pietrangeli.

[19] In 1967 Krishnan won the Antwerp International Championships on red clay a second time by beating Emerson in the final in three straight sets.

India surprised West Germany in the inter-zonal semi-finals with Krishnan beating Wilhelm Bungert (a Wimbledon finalist later that year).

[25] Krishnan was a regular player on the Indian Davis Cup team between 1953 and 1975, compiling a 69–28 winning record (50–19 in singles and 19–9 in doubles).

[27] Critics hailed Krishnan as a marvel, Lance Tingay of The Daily Telegraph described his tennis as "pure oriental charm" while another described his style as "Eastern magic".

[28] Rafael Osuna, Nicola Pietrangeli and Krishnan's son Ramesh were some of the other notable exponents of this style, emphasizing finesse.

Ramesh Krishnan emulated his father's achievement of winning the Wimbledon junior title, and went on to become a leading Indian tennis player in the 1980s.

[citation needed] On 25 July 2012, Ramanathan Krishnan re-launched India's premier English-language weekly sports magazine, Sportstar, at a function in Chennai.