As the extraordinary Beppe Grillo has spent the last few weeks demonstrating to the acute consternation of the entire European political class, Italians are never more dangerous than when they are dismissed as clowns. The Azzurri were deadly serious opponents for England yesterday – to be sure, there were precious few signs of red-rose laughter at any point during a tourniquet-tight contest – and while the big prizes are still available to Chris Robshaw and company, they will not travel to Wales for the weekend's finale in the best of spirits.

The deeply alarming truth of it was that the overwhelming favourites spent the last quarter of an hour fighting tooth and nail, and then hanging on for dear life. But for some missed kicks by the Italian outside-half Luciano Orquera and a couple of fumbles in contact just when the home defence was beginning to crack and splinter, the Grand Slam dream would have evaporated and the Welsh would be front-runners to land another Six Nations title. Stuart Lancaster, the England head coach, was not joking when he admitted afterwards that his side will have to deliver improvements across the board and off the scale to hold the resurgent Red Dragonhood when they venture across the river Severn.

All things considered, he was not in the mood for wisecracks. Not only did his charges end the afternoon in the tryless state to which they are becoming too accustomed for comfort, they also allowed the rank outsiders in blue to show greater adventure – and, yes, greater class – with ball in hand.

Perhaps the Twickenham crowd, positively awash with smug assumption before kick-off, expected to see something special from the Azzurri captain Sergio Parisse – by common consent the best No 8 in world rugby and the one Italian who could demand a place in any international side, including the All Blacks.

Parisse was indeed brilliant: his attacking double act with Alessandro Zanni down the narrow channels was every bit as accomplished as his peerless aerial game and his perfectly timed tackling around the fringes of ruck and maul. But there were other striking contributions, particularly from the visiting back three, that few predicted, or even thought possible. If the sole Italian try, which arrived eight minutes into the second half, was the result of an English muddle – Danny Care managed to propel a bog-standard clearance in the wrong direction, while Chris Ashton's positional discombobulation allowed Luke McLean to maximise Orquera's kick to the corner with a minimum of fuss and bother – there could easily have been a couple of others. England, meanwhile, were restricted to half a dozen penalties from the boot of Toby Flood. It was a deeply unsatisfying return.

Lancaster's side began well enough, with Mako Vunipola, on his first international start, sending the infinitely more experienced Martin Castrogiovanni skywards as the packs met for their initial stag-fight scrum. Castrogiovanni was duly penalised, Flood took advantage with a left-sided goal and the pre-match script was being followed.

By the end of the first quarter, Flood had doubled his tally and Vunipola was having himself a party, in open field as well as at the set-piece. But Zanni and his equally impressive fellow forward Leonardo Ghiraldini earned Orquera a shot of his own with some aggressive work from an attacking line-out, and when Parisse treated the Twickenham multitudes to a glimpse of his genius down the right, only a dodgy knock-on call from the referee George Clancy saved England from a nasty blow to the solar plexus.

At this stage, the Italians did not look like a team who thought they could win. They were, however, super-strong in defence. Gonzalo Garcia missed next to nothing in midfield, where England's creativity deficit was again evident for all with eyes to see, and there were some brave interventions from the long-serving Andrea Masi, who put in a serious shift at full-back. Even when the Azzurri defensive system malfunctioned, England could not find a way to cross their line. One attack, which briefly offered them a five-man overlap, ended with Flood chasing the try himself and being held up my Masi and the scrum-half Edoardo Gori.

When Gori was dispatched to the cooler after having a low kick charged down by Flood and then obstructing the Leicester player as he looked to capitalise, it seemed likely that England would up the tempo and send the scoreboard spinning. Frustratingly for them, they had to settle for two more three-pointers from the kicking tee, although Ashton might have made more of a break down the right shortly after Gori's departure.

Back to full strength after the interval, the Italians grew to their full size while England shrank, man by man. A further exchange of penalties preceded McLean's try and when Giovanbattista Venditti swatted Mike Brown aside in the course of a rampage down the right – Manu Tuilagi and Brad Barritt also failed to bring the wing to earth – Orquera was granted another shot at the sticks. Had he nailed it, the Azzurri would have been within a point of squaring it. Sadly for him and his kind, he missed.

Yet there was not the slightest hint of the Italians reluctantly giving it up as a bad job. Even when Tom Youngs, one of the brighter performers in the England side, scrambled effectively in the visiting 22 to earn Flood the last of his penalties, Parisse and his courageous colleagues sucked in air, puffed out their chests and went after their hosts with renewed vigour. At the death they pieced together a long, multi-phased attack – Tobias Botes, the replacement half-back, was particularly clever in orchestrating the production – and would surely have scored but for Davide Giazzon's handling failure at the crucial moment.

So it was that Lancaster's men dodged perhaps the most dangerous Azzurri bullet ever fired in their direction. They will feel suitably relieved, but also apprehensive. Wales are now within a single-score victory of denying them both the title and the Slam. They have six days to get a grip.

England: man for man

15. Alex Goode

Much of the intelligent attacking work came from the Saracen, but his levels dropped after break. 5.5/10

14. Chris Ashton

Improvement in physical chores, but positional awareness lacking. A wing in need of GPS. 4.5/10

13. Manu Tuilagi

As anonymous as he has ever been for England. No Italians ran through him, he ran through no Italians. 5/10

12. Brad Barritt

Even the one-man barricade was stormed and, while he didn't break, attacking limitations were clear. 5/10

11. Mike Brown

Might have scored a chaser's try in first half, but could easily have cost England seven points in second. 5/10

10. Toby Flood

Played flatter than Owen Farrell and gave England width, but his butchery of an opportunity before the break was criminal. 5.5/10

9. Danny Care

Too harem-scarem for comfort, he made Italians' try for them with kick that was an affront to technique. 4/10

1. Mako Vunipola

England's most effective player with his heavy-duty scrummaging, ball-carrying and ruck-setting. His substitution was mysterious. 8/10

2. Tom Youngs

Eye-catching. Hooker with centre's hands was excellent in contact. 8/10

3. Dan Cole

More comfortable at the set piece than against France and handy presence in hurly-burly of the loose.7/10

4. Joe Launchbury

Continued to look part. New-age forward made athleticism count. 7.5/10

5. Geoff Parling

Failed to last but had been busy on the carry, if not most powerful. 5/10

6. James Haskell

Started with a roar, but England were a footballer short in back row. Substitution was predictable.5.5/10

7. Chris Robshaw

No "man of the match" this time. Worked socks off but Italian back-rowers finished in ascendancy.6/10

8. Tom Wood

There's playing out of position, and then there's playing out of position against Parisse. Enough said. 5/10

Best off the bench: Ben Youngs

Energetic and on the money with tactical kicking.7/10