Captain David McCann delivered a man-of-the-match performance and Thomas Ahern touched down twice in the Ireland Under20s' outstanding 39-21 bonus point win over England at Franklin's Gardens.
Bandon's Jack Crowley was on kicking duty again and continues to impress in the pivotal out-half role.
England came into this top-of-the-table encounter with a formidable record, having won 23 of their last 26 U20 Six Nations home games, but Noel McNamara's young guns played some of their best rugby of the season so far in a stylish six-try victory.
With the leg-pumping Ireland forwards in dominant form, tries from Alex Soroka, on his full debut, Hayden Hyde, Ahern and Ethan McIlroy saw the defending champions surge into a rousing 29-7 half-time.
That flood of scores overshadowed England lock George Hammond's initial ninth-minute try, and it was an evenly-contested closing 40 minutes during which pacy replacement O'Reilly and Ahern cancelled out converted scores from Hugh Tizard and Theo Dan.
Ticking off the Triple Crown tonight, the Ireland U20s have now won seven of their last ten away matches in the Championship. They are now six points clear of second-placed England, with France a further two points behind, ahead of their penultimate round clash Italy in Cork in two weeks' time.
Andrew Smith and returning centre Hyde both threatened out wide as Ireland were quick to exploit space on the edges. The forwards rumbled up close from a penalty advantage before Jack Crowley clipped over a straightforward place-kick for a fifth minute lead.
Ireland's advantage was short-lived, though, as England hit back with seven points from their first serious attack. They went to the left corner from a penalty, a peel move seeing Rusiate Tuima batter through before second row Hammond burrowed over from the ruck.
A slight knock-on from talismanic number 8 McCann denied him a try at the end of a promising set of attacking phases, Ireland remaining on the front foot as ever-present tighthead Thomas Clarkson forced a maul turnover to make up for his earlier concession of a scrum penalty.
Maintaining a high tempo off Lewis Finlay's inviting passes, the dynamic and athletic Irish pack carried strongly again to set up the 18-year-old Soroka to drive low and ground the ball past two defenders. Crowley could not convert but soon popped up with a crucial turnover penalty to thwart the home side.
Continuing to get over the gain-line with McCann leading the carry statistics, Ireland swept out to the right in the 27th minute when a couple of brilliant offloads from Sean O'Brien and McIlroy - the Ulster winger outfoxed two defenders with a behind-the-back pass - sent the supporting Hyde over for Crowley to crisply convert.
John McKee tore forward almost straight from the restart, England being forced through some energy-sapping phases. Armed with a penalty advantage, lovely hands from the fast-breaking Oran McNulty and Hyde saw McIlroy had a cut at the try-line before a powerful finish from Ahern, who was well-supported by McKee.
Crowley added the extras with aplomb to make it 22-7, the influential Cork native immediately departing for a HIA but Ireland squeezed in a late bonus point score just before the interval. Crowley's replacement Tim Corkery converted in confident fashion after Hyde's slick one-handed offload had played in McIlroy close to the right corner.
England gained early momentum in the second half, aided by their front row replacements. Centre Charlie Watson's incisive run took him close before lock Tizard wrestled his way over from close range. George Barton converted to cut the gap back to 15 points.
England came in search of another quick-fire try, but Ireland earned turnover ball from a choke tackle and a McCann breakdown win. They soon rampaged forward for try number five, McNulty bouncing off Tom Roebuck's tackle to feed O'Reilly who darted past halfway and then took a return pass from Smith to scramble over past Barton's last-ditch tackle.
Crowley was annoyed to send the conversion wide, and England fired back swiftly with a well-finished 56th-minute maul try from hooker Dan, converted by Barton for a 39-21 scoreline. The pace slackened on the hour mark, the home crowd raising the decibel level as McNamara's youngsters found it more difficult to gain ground.
Crowley and Brian Deeny stepped up with some important plays, the out-half launching an excellent clearance kick downfield and the tireless second row frustrating England with a hard-earned turnover penalty.
Showing their alertness to another turnover, replacement Tom Stewart scooped up a 73rd minute pass dropped by Tuima, and although Doherty managed to bring down McNulty a few metres short, Ireland made sure the counter attack ended with the clinching try - Ahern muscling over the whitewash with two men on the latch.
Scorers for England: Try: George Hammond, Hugh Tizard, Theo Dan; Cons: George Barton 3.
Ireland: Tries: Alex Soroka, Hayden Hyde, Thomas Ahern 2, Ethan McIlroy, Max O'Reilly; Cons: Jack Crowley 2, Tim Corkery; Pen: Jack Crowley