Ireland were on the brink of sealing the title but England worked their way to within a few metres of the line and, with a penalty advantage, Smith had a free shot at goal, which he took to finish a frantic game.
The Championship will now go down to the final day, with Ireland needing to beat Scotland at the Aviva Stadium to become back-to-back champions. If they lose, it could open the door for England, who play France later on Super Saturday.
Regardless of what happens next week, this is a result and performance England have been waiting for and hints at what the future might hold.
They played with an intense ferocity for the full 80 and did not allow their setbacks to derail their positivity. Against any other opponent, they might have been home and dry long before the 80 but Ireland were incredibly resilient.
No team wins 11 Guinness Men’s Six Nations matches on the spin without facing some adversity and Ireland dug deep and so nearly won it all.
Ollie Lawrence scored an early try for England but Jack Crowley kicked four penalties to put Ireland 12-8 in front at half-time. James Lowe then scored the first of two tries, but England rebounded when first George Furbank and then Ben Earl crossed to put them ahead.
Lowe’s second looked to have sealed the title for Ireland but Smith’s late drop goal sent Twickenham crazy – and sent the Championship to Super Saturday.
ENGLAND PUT IRELAND UNDER THE MICROSCOPE
Ireland, so calm and collected throughout this Championship, made a clinical start and took the lead within the first two minutes as Crowley kicked an early penalty when England were caught offside at the breakdown.
The home fans had barely taken their seats after the national anthem and their team was behind, but they were soon out of them again as England responded with a fabulous try.
Tommy Freeman bounced off a thunderous Calvin Nash tackle in midfield, and England took advantage of the overlap down the left, as Henry Slade released Lawrence and he held off Crowley to plant the ball down in the corner.
Captain Jamie George issued a rallying cry to the home fans to bring the noise, and they responded in kind. Twickenham was bouncing and, Ireland for the first time in this Championship, had their hands full as England tore into them with immense physicality.
George Ford may have missed the conversion but he added a penalty in the 17th minute to extend their lead to five, but Crowley responded with his second penalty just three minutes later.
England had their tails up but Ireland soon started to find their feet at the breakdown, with Tadhg Beirne turning the ball over on his own line. They then survived a knock-on call a few minutes later when Lawrence thought he scored a second try after chasing his own kick but the play was brought back for a George Furbank handling error.
England’s near-misses continued as Ford then missed a very makeable penalty from Ireland’s 10-metre line, and he was punished when Ollie Chessum was penalised for not releasing the ball near halfway, and Crowley kicked Ireland ahead.
The No.10 was nerveless in front of goal and he added a fourth penalty when George Martin was caught offside in the 22.
SMITH DENIES IRELAND
Perhaps fortunate to lead based on the balance of play, Ireland grabbed the game by the scruff of the neck and silenced Twickenham with a sensational try just four minutes into the second half.
A brilliant kick chase from Hugo Keenan set Ireland up in midfield, and they moved it wide quickly and beat England’s blitz defence with some precise passing. It eventually made its way to Lowe, who sprinted to the corner and slid over to put Ireland nine points ahead.
Crowley missed the conversion – his first miss of the day – but with a nine-point lead, it seemed Ireland finally had one hand on the trophy until England flipped the game on its head.
George Martin and Maro Itoje combined to send Furbank clear down the left and the full-back slid over untouched to cut the gap back to four points. Ford could have reduced it further but his kicking struggles continued, as he pushed another effort wide of the posts.
England had their tails up, and soon after they were a man up as Earl made a break from midfield and carried England just shy of the 22. As he was brought down and England prepared to quickly move it left, Peter O’Mahony, in his desperation to prevent English quick ball, dived over it and killed the move, resulting in an instant yellow card.
England went to the corner and, with a penalty advantage, scored their third try as Earl muscled his way over from five metres out to give them the lead. Smith, on for Ford, landed the conversion to make it 20-17 ahead of the final quarter.
There was a further roar when Danny Care came on to win his 100th England cap but Ireland held firm for the rest of O’Mahony’s sin-bin and then struck just a minute after his return to regain the lead.
With the ball in England’s 22 and a penalty advantage, they moved it left again as Crowley and Jamison Gibson-Park combined to set Lowe free again, and the winger powered through Smith to dot down in the corner.
Crowley missed the conversion to leave Ireland 22-20 ahead, but England had a chance to take it back almost straightaway when they won a penalty just inside their own half. Elliot Daly, only on 10 minutes prior, lined up a kick at goal and, while it had the distance, it lacked the accuracy and fell the wrong side of the post.
England were then reduced to 14 men when Chandler Cunningham-South went off injured but they still worked their way into the Ireland 22, where Smith won the game.
