R Ashwin reveals the toughest opponents he has faced ahead of his 100th Test

R Ashwin is always up for a challenge and two days from his landmark 100th Test, India's premier off-spinner looked back at the on-field battles he has enjoyed in international and domestic cricket.

Ahead of the fifth and final Test against England, the visitors' batting mainstay Joe Root spoke glowingly of Ashwin and on Tuesday, the 37-year-old returned the compliment.

Besides Root, Ashwin said Steve Smith and Kane Williamson also brought the best out of him.

"I have loved bowling to Steve Smith, Williamson and Joe Root. They are some of the finest batters going around the world now," said Ashwin.

"When I played first-class, I had the privilege of bowling to some of the gun batters of spin - I have bowled to S Badrinath at the Tamil Nadu nets and he was one of the finest batters of spin, then Mithun Manhas, Rajat Bhatia (both from Delhi).

"These are some of the greatest batters of spin who I would have not wanted to encounter in international cricket. They were my finishing school before I went on to play international cricket.

"I'd like to take my hat out to them because they gave me some valuable lessons," said Ashwin.

Ashwin is someone one who has reinvented his game across formats through his career. He made his white-ball debut for India before playing Test cricket largely due to his exploits for CSK in the IPL.

However, Ashwin insisted he got the opportunity to play for India not only because of his white-ball skills.

"I am treading a very careful line of not making this a punch, but it is more of a lack of understanding when you say that I came through the T20 format. I had a good 30-40 matches in first-class cricket before I made it to the Indian team," he said in response to a question.

Ashwin remains a regular in club cricket when he is not on national duty.

"In the same year I made my Test debut (in 2011), I got a fifer in the Rest of India game for ROI side in the Irani Trophy. I had played 3-4 seasons of club cricket in Chennai.

"You might say there's a standard difference, but I played 3-4 years of club cricket there, probably mentored by seniors, told where I made mistakes, corrected my discipline, bowled long spells.

"It really builds your resolve as a cricketer when you do all those things. T20 happened by accident. I didn't know what T20 cricket was like. Played SMAT in 2008 for the first time, we were the winners.

"Got a CSK contract, which also happened because I got a fifer in a 50-over game playing club cricket in Chennai." Ashwin, who recently became only the second Indian after Anil Kumble to cross 500 wickets in the game's longest format, made his Test debut in 2011 and has enjoyed more highs than lows during a 13-year journey.

"A lot of things need to go your way when you have to get a breakthrough and also continue playing for a so many years. I am indebted for all those things, but I definitely wouldn't agree that I came through the white-ball formats. It was the other way round," he said.

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