Courtney Lawes says the competition for places in the England squad is driving him to new heights as an international player.
With George Kruis injured, Lawes and Joe Launchbury have started in the second row so far this Six Nations, with Maro Itoje switching to the flank.
"I've had to raise my game," Lawes, 27, told BBC Radio 5 live.
"I've had to push myself a lot harder in the last year and a half than I have done previously in my career."
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The Northampton lock added: "It's really good for me because I get to really find out where my potential is and how far I can go."
And while he says he is playing "near enough" the best rugby of his 55-cap England career under Eddie Jones, Lawes feels there is still more to come.
"I'm just really looking forward to pushing on, keeping on going, because I still have a lot more to give," he said.
In his 13 appearances under Jones, Lawes has excelled in terms of tackling and ball-carrying, with the head coach citing a marked improvement in his performances.
"I've just started ball-carrying again," Lawes said.
"I've always been pretty solid in defence, but the biggest change has been getting my hands on the ball and being effective there.
"Eddie told me from the start he wanted me to be a big hitter and a big ball carrier, and that's what I am going to be for him."
Defending champions England beat France and Wales in their opening 2017 Six Nations games and face Italy at Twickenham next - on 26 February - as they seek extend their national record of 16 Test victories in a row.