England need to improve their discipline, captain Dylan Hartley said after his side's 21-10 win over Ireland at Twickenham in the Six Nations.
The hosts, who are unbeaten in the championship and remain on course for a Grand Slam, had James Haskell and Danny Care sin-binned in the second half.
"The boss believes we left some opportunities out there and I fully agree," hooker Hartley said.
"I'm sure there's plenty to work on, discipline being top of the list."
England head coach Eddie Jones said the victory over the defending Six Nations champions showed his side are an improving force, however.
"Our performances have stepped up," the Australian said after his first match in charge of England at Twickenham.
"We probably left 10 to 15 points out there as we couldn't always convert our attacking pressure."
|Eddie Jones' England moving in the right direction|
|"No coach, no matter how long in the tooth or wise of thought, can rapidly transform a nation who have won just one Grand Slam in two decades.|
|"What will give Jones hope that over the next few years he might succeed where others have failed is the emergence of the sort of player that successful teams can be built around."|
|Read chief sports writer Tom Fordyce's analysis|
England completely dominated the visitors in the first half but went into the break with a slender 6-3 advantage before breaking loose in the second half.
Two tries in five minutes from Anthony Watson and Mike Brown put the hosts on course for victory against an Ireland team shorn of key players through injury.
With Wales next to visit Twickenham in a fortnight, talk will turn to a possible Grand Slam for the men in white and the chance to end four successive years of finishing as runners-up.
Holders Ireland, on the other hand, have now failed to win any of their opening three matches and are second from bottom of the table with a single point.
Jones threatens media ban
The former Australia and Japan boss had riled Ireland in the build-up by suggesting the parents of fly-half Jonathan Sexton, who has a history of concussion problems, should be concerned for his welfare.
But with England's next opponents Wales, whose coach Warren Gatland is renowned for pre-match mind games, Jones said: "I'm putting a self-imposed media ban on myself before the Wales game.
"I will leave that to Warren Gatland, he's pretty good at it."
When asked if he regretted mentioning Sexton's parents, Jones replied: "I don't regret anything. Why would I regret it? Ireland said he had whiplash injuries, not me.
"It's a sideshow - it's finished. The main event is over."
'Vunipola could be special'
Number eight Billy Vunipola was a destructive force, his barnstorming bursts punching holes in Ireland's defence and creating space for his team-mates.
Of the Saracens player, Jones said: "Vunipola was great. He just loves playing rugby. He loves the team environment and loves playing for England."
Former England captain Chris Robshaw also praised Vunipola's impact.
"Over the last year he has really stepped his game up," said Robshaw. "Before that he was a great player. Now he has gone to another level.
"If he keeps playing like that he is going to be pretty special."