Centres Sam Burgess and Henry Slade are putting pressure on their rivals for a place in England's World Cup squad, says coach Stuart Lancaster.
The duo made their England debuts in Saturday's win over France and Lancaster has to name his 31-man squad by 31 August.
"Two guys, Burgess and Slade, pushing late put the pressure on in terms of the other players," said Lancaster.
"It will be interesting to see how they respond."
Lancaster is expected to name four centres in his squad.
Brad Barritt and Jonathan Joseph are considered his first-choice pairing at centre, while Luther Burrell was also expected to make the final cut - until the performances of Burgess and Slade.
Burrell, however, should get his chance to impress when England play France again on 22 August, with Tom Youngs, Joe Launchbury, Courtney Lawes, Chris Robshaw and Billy Vunipola also set to return to the side.
And on Burrell Lancaster said: 'It will be interesting to see how he goes because there will be a spotlight on him and there will be pressure on him. You need players who can deal with pressure and deliver on the day — as the two guys did last week."
Billy Twelvetrees is another vying for a centre role, and Lancaster added: "It's that position in particular that is taking up most of the time in selection."
Former England scrum-half Matt Dawson believes ex-rugby league player Burgess, 26, should not be picked by Lancaster.
"Everyone is entitled to their opinion," said Lancaster. "We've got far greater knowledge of what is going on inside the camp and how he is progressing.
"I thought he got a lot of what he needed to do right [against France]. It was a big game for him. To come in and play your first cap against a side of the quality of France and make the impression that he did, I thought he did great to be honest."
He added: "He's learned and developed right the way throughout this camp. It was pleasing to see him replicate that in the game."
|England's World Cup warm-ups|
|England 19-14 France|
|France v England, 22 August|
|England v Ireland, 5 September|