"It is a big game psychologically for both teams because we have to go there next year as well and that is going to be even bigger than this Sunday," Gatland said, mindful that with Australia also in England's group and only two to qualify for the knockout stages, any advantage gained now may be important then.
"If we can win that will be four in a row [against England - something Wales have not done since the 1970s], and if we then win the Six Nations, you start to have a few doubts."
At a stroke, the stakes for Monday's encounter have been raised. Gatland has proved a master of the big moment, whether with the Lions last summer, or Wales in securing two Grand Slams as well as last year's title, whereas England under Stuart Lancaster have yet to see a tangible return on their promise.
Both teams are very much in the hunt for Six Nations silverware this season, tied with Ireland and France on two victories apiece.
Gatland knows the value of having proven warriors in his task force. He is also a man who trusts certain players, or a certain type of player, and that is why he had no hesitation in summoning outside centre Jonathan Davies to the cause even though the Lions test player has not started a match since injuring pectoral muscles against South Africa on November 9.
Davies has had only 105 minutes of rugby since November, not much more than England's Manu Tuilagi, a player Gatland singled out yesterday as one of the few in the England set-up with "X factor".
Lancaster has said he thinks an immediate return for Tuilagi would be too big a step up. But Gatland has gone for broke with Davies because he knows the calibre of the man he preferred to Brian O'Driscoll for the third Lions test against Australia.
"It wasn't difficult to make the call as Jonathan has been really, really sharp in training. It's just that he has not had a lot of rugby," said Gatland.
He has also recalled lock Alun-Wyn Jones, who has recovered from the foot infection that caused him to pull out just before kick-off against France a fortnight ago.
Davies himself agreed that he had been "climbing up walls", looking for the chance to get back on to the pitch.
Even though Wales were listless against Italy and dreadful in defeat against Ireland, they raised themselves for a rousing performance against France, stung by barbs from Gatland. Twickenham holds no terrors for Gatland, who has won there many times with Wasps as well as Wales.
Six Nations
Ireland v Italy
Dublin, 3.20am tomorrow
Scotland v France
Murrayfield, 5.50am tomorrow
England v Wales
Twickenham, 3.50am Monday