But Chase insists that the fierce rivalry the two players enjoy with their respective West Yorkshire clubs does not affect their relationship on the international stage.
"We test each other and bash each other every time we play each other in the Super League, but when we come here we leave whatever happens on the field there, and we are as one," he said.
"Everyone is getting closer together and we're getting to know each other better, which makes us much tighter as an England group.
"It's getting better every year, and if we can keep improving in that respect in 2013 then I think we will go a long way at Rugby League World Cup 2013."
The pair were speaking while in camp with the Elite Training Squad at their state-of-the-art facility in Loughborough, where the team resumed preparations for RLWC2013, and next month's International Origin showdown with the Exiles.
And Sinfield admits that June's match action represents the most important element of the team's preparations for this autumn's challenge.
"It's been great. Preparations over the last three years through working with staff and getting everything in place is something we're reaping the rewards of," he said.
"But, while doing the prep at the camps is all well and good, and we have got a lot out of them, there's no better preparation than a run out together in a test match scenario.
"The Exiles fixture is one we want to win as a stand-alone match. It's a great test for all of us. There's some fantastic players in their squad and they'll want to win, I can assure you of that.
"But it'd be great for us as a group to go into that World Cup having extended our unbeaten run from the Autumn Internationals - a real shot in the arm."
Chase echoed his team-mates sentiments, emphasising the importance of this year's showdown at the Halliwell Jones Stadium on June 14.
"It's a real stepping stone and something to give us a good test. It's World Cup year, so it'll bring the best out of us," he said.
"Everybody's competing against each other, and with one another in the England team for a place in the squad at the end of the year.
"When we get to the Exiles game, it's a real opportunity. We all know that."
Tickets for the International Origin match are available at www.englandrl.co.uk/tickets, while tickets are also on sale for RLWC2013, with 55% priced £20 or less.
To make sure you will BE THERE buy now at www.rlwc2013.com or call our 24 Hour Ticket Hotline on 0844 847 2013