England will enter the World Cup armed with a confidence-enhancing 21-13 victory over Ireland but will know they should have emerged more convincing winners over the RBS 6 Nations champions in their final warm-up game.
Jonny May and Anthony Watson ran in tries inside the opening 15 minutes as the tournament hosts honoured their promise to address the shortcomings exposed during two poor performances against France.
They attacked the breakdown with far greater energy and relentlessly hunted down green shirts, with captain Chris Robshaw at the heart of his pack's pursuit in an afternoon that restored the forwards' reputation after their humbling in Paris a fortnight ago.
When Ireland scored with half an hour remaining, however, what should have been an emphatic seventh successive triumph at Twickenham became far closer until Ireland fell away in the final 10 minutes.
Sam Burgess arrived from the bench for the final quarter and gave a glimpse of what he might be able to achieve with more time, almost succeeding with one offload amid two handling errors.
Tom Wood was named man of the match but Robshaw could have also finished with that accolade, and it was two late penalties from replacement fly-half Owen Farrell that swept the Red Rose home.
England, whose line-out and set piece were improved but still fell short of the usual standard, enter their World Cup opener against Fiji on September 18 with some momentum while accepting higher standards will be needed for the Pool A clashes with Wales and Australia.
Ireland will take comfort in knowing they do not need to peak until October 11 when they play their pivotal Pool D clash with France and on this evidence their conditioning levels are below that of the hosts.
They will monitor the fitness of Conor Murray carefully over the coming days after the Lion departed with concussion early in the match, his good health critical given he is one of only two scrum-halves in the 31-man squad named for England 2015.
England's start could not have been more emphatic as waves of attacks ended with Ben Youngs floating a clever pass to May who bumped off Tommy Bowe and evaded Simon Zebo to score in the left corner.
The one-way traffic was temporarily interrupted when Jonathan Sexton landed a penalty on the crossbar with the ball bouncing over, but in the 14th minute England struck again when George Ford sent a cross-field kick to the right wing where there was acres of space.
Watson and Zebo leapt to compete for the ball and it was the Ireland full-back who miscalculated, allowing Watson to collect and touch down.
A bad start deteriorated further for the Six Nations champions when Murray's match was ended by concussion and a forward pass from Youngs saw May denied a third try.
Geoff Parling, restored to the team to stabilise the line-out after two shaky meetings with France, stole Irish possession at the set piece and England renewed their assault with the slippery Watson almost wriggling free.
The pendulum swung just before half-time, however, as Ireland finally attacked with accuracy, but a gap for wing Dave Kearney was quickly filled with white shirts before Sean O'Brien knocked-on.
Ireland began the second half with a flourish and it was a more finely balanced game now as Ford and Sexton exchanged penalties.
May was forced into a rushed clearance from behind his own whitewash and Joe Schmidt's men pounced from the short-range line-out, forwards peeling off around the fringes until O'Connell arrived to burrow over.
England led just 15-13 but they almost responded instantly when Ford and Watson escaped the green shirts only to fall to despairing late tackles.
The World Cup hosts were back in control as they searched for the match-sealing try and it appeared to have been scored with 10 minutes left only to be disallowed because of a mix-up between Tom Wood and Robshaw.
Substitute Owen Farrell, who had earlier butchered an overlap, landed two penalties to put the result beyond doubt and ensure England will enter the World Cup unbeaten at Twickenham this year.