Curry’s red card meant Steve Borthwick’s side played all but three minutes of the Pool D opener at Stade Velodrome with 14 men, yet they rose to the challenge magnificently to produce their most resilient display since Sinfield was placed in charge of the defence 10 Tests ago.
It was a department of England’s game that was under close scrutiny after they had conceded 30 tries in nine matches, but even with Curry watching from the stand their tryline remained intact until the final minute.
“We showed a bit of what we’re about and I still feel there’s loads of improvement in us,” Sinfield said.
“We’re disappointed to concede at the end, but I thought we did a really professional job.
“We knew that performance was coming and to have to do the vast majority of it with 14 men shows the fight and the spirit that we have spoken about for some time now. However, it wasn’t being transferred onto the field.
“It was pleasing to see some aspects really improve, but more so for the players because they’ve seen what this group is capable of.
“And we need to ensure we get more of that and keep moving forward in each of our training sessions.”
Curry is to attend Tuesday night’s independent disciplinary hearing in Paris in person as England seek a favourable outcome to his dismissal after a clash of heads with Mallia.
The Sale flanker, who was making his first appearance since the autumn because of hamstring and ankle injuries, is facing a suspension in the region of three matches, which is likely to be reduced by one if he attends tackle school.
Offsetting his unavailability, however, is number eight Billy Vunipola’s return from his ban for a dangerous tackle against Ireland for Sunday’s second group match against Japan in Nice.
George Ford is the man of the moment after he masterfully guided England to victory against Argentina, who entered the match as favourites but proved to be a disorganised rabble.
Ford’s brilliance poses a selection conundrum for Borthwick given squad captain Owen Farrell comes back from suspension – also incurred for a dangerous tackle – against Chile on Saturday week.
Both are vying for the fly-half duties and while Ford is sure to be rested against the South Americans due to his heavy workload, Borthwick will need to make a difficult decision for the Pool D finale against Samoa.
“It was a masterclass from George. He really grabbed hold of the game for us. He managed it really well and he was faultless with the boot,” Sinfield said.
“He brings a calmness to us. You want your leaders to step up in a variety of different ways in big games and George certainly did that.”