India skipper Virat Kohli says off-spinner Ravichandran Ashwin's form in a long home season will be key to how long India can stay at the top of the International Cricket Council's Test rankings.
Kohli was presented with the ICC Test Championship mace for the No.1 team on Tuesday after India's 3-0 series sweep against New Zealand at Indore's Holkar Stadium.
Ashwin claimed 13 wickets in the final Test to spin India to a comprehensive victory and bag the man-of-the-match award.
Quick single: Ashwin leads India to series sweep
His 27 wickets from three matches also earned him his seventh man-of-the-series award in 14 series, underlining the spinner's importance in the side.
"It's an exciting thing to talk about his stats out there in the middle, it's a topic of discussion for us," Kohli said.
"He's been a champion. I hope he can keep going through this long home season and keep the team at the top where we are."
The series against New Zealand marked the beginning of India's bumper 13-Test home season and Ashwin's form would be crucial again when England and Australia come calling.
It was Ashwin's fourth successive man-of-the-series award and the 30-year-old said he felt he was in peak form.
"I feel really good about myself. I've been bowling really well and my confidence is really sky-high," he said.
A shrewd spinner known for his penchant for outwitting key batsmen, a reputation he enhanced by dismissing Kiwi captain Kane Williamson in both innings in Indore, Ashwin exploited footmarks and varied pace in another spin masterclass.
"It was a wicket where you had to work hard, be patient and bowl good lines," Ashwin said, also explaining why he bowled slower than usual.
"This wicket didn't have a lot of bounce. It was not going to short leg or backward short leg, so I had to get them to drive.
"I got a bit of footmarks outside right-hander's off-stump and I wanted to get them lunging outside by bowling a lot wider outside off-stump and the results are there to see."