Perth: Question marks have been raised about their ability to trouble batsmen in overseas conditions but spin twins Ravindra Jadeja and Ravichandran Ashwin have proved their critics wrong with an impressive start to their World Cup campaign, feels team's premier batsman Virat Kohli.

With convincing wins over Pakistan and South Africa in the first two games, no one can deny the role played by off-spinner Ashwin and left-arm spinner Jadeja.

Between them, they have taken six wickets (4 for Ashwin and 2 for Jadeja), having collectively given away only 175 runs in 36.2 overs at an economy rate of less than five runs per over (4.83).

"If you see, they were our two main bowlers in the Champions Trophy in England. Jadeja was adjudged 'Best Bowler'. No one then had expected that our spinners will become our main bowlers. They proved everyone wrong then and even if you see here in Australia, they are again doing well, Kohli gave his observation on the performance of the duo before the match against South Africa.

As per vice-captain Kohli, the duo have proved how true the old adage 'offence is the best defence' is. He doesn't believe that if one plays an attacking role, the other needs to don the defensive hat.

I think, first and foremost, your mind-set should be to take wickets. Ashwin had that mind-set in the first game (vs Pakistan). Jadeja is always an attacking bowler and if gets a bit of assistance, he becomes even more dangerous. We saw that during Champions Trophy in England,"Kohli said.

The duo hasn't been taken apart by the two quality teams in the first two games and Kohli feels that on big Australian grounds, one can be rewarded if the homework is done properly.

"In Australia, you have long boundaries, square boundaries. If you bowl intelligently, you will be rewarded. They have been our main bowlers for some years now and they haven't done badly in Tests either."

Kohli completely agrees that not only fast bowlers but spinners also hunt in pairs and it's upto the duo to devise a plan as to who would go for wickets and who would like to bowl wicket-to-wicket.

"I think their bowling partnership is very important for us. Between the two, they will have to realise, who is going to be aggressive and who is going to play the supporting role," he observed although his own take is to attack from both fronts.

If both are aggressive and get 3-4 wickets in an innings, that obviously will be good for us but they are wise and know when to play what role and obviously MS is there to help. So, I think their partnership will be crucial for us," he said.

Kohli was effusive in his praise for Ashwin.

"Ashwin is a very skillful bowler, and I think he's at his best when he wants to take wickets. Against Pakistan, he was on top of the batsmen the whole time. It's more of a mental battle going on the field, and I think he was on the top most of the time when he bowled. To be honest, those maidens in that (1st) match, proved to be the game-changer."

Kohli was even more elated about Ashwin's effort considering it's not easy as a spinner to bowl with five fielders inside the circle and at times one shouldn't just look at the wicket but holistically on the impact that even maiden overs can have, on opposition batsmen.

"Ashwin only got a wicket against Pakistan, but the way he bowled was absolutely outstanding, especially when you take into consideration you have five fielders in the ring and their spinners could not contain us so much, and the way he bowled in that wicket was pleasing to watch.

"He will be a key factor for us as long as he can be in that same mindset that he was in that first game and hopefully he can sustain that through the tournament," Kohli added.