England and Scotland each came from behind to win their London Sevens quarter-finals on day two of competition at Twickenham.
Scotland overcame a 21-0 half-time deficit against New Zealand to book their place in the final four, while England scored a try after the full-time siren to defeat series champions South Africa 17-12.
The Scots will now face the United States in their semi-final, with hosts England set to do battle with Argentina's conquerors Canada.
Scotland score 24 unanswered points after the break to stun Kiwis
At half-time of their quarter-final, it looked as though reigning London Sevens champs Scotland would fail to complete their trick, staring down the barrel of a 21-0 deficit to New Zealand.
Sam Dickson, Fa'ausi Fuatai and Andrew Knewstubb each crossed for tries in a dominant first-half for the Kiwis, but a try double early in the second half from Dougie Fife got Scotland back into the game.
In similar circumstances to last year's final win, Jamie Farndale crossed in the corner with 30 seconds left on the clock to cut the deficit to two, before Scotland regained their own kick-off and completed the thrilling comeback with Farndale touching down once more.
The Scots will face the United States in the first semi-final, after Perry Baker scored a hat-trick in their 31-7 victory over Australia.
Norton scores with final play as England down series champions
In the third quarter-final, hosts England took on series champions South Africa, and it was the English who took an early lead, with Dan Norton scything through a gap in the defence to dot down.
They're not runaway series champions for nothing though, and the Blitzboks hit back either side of half-way, with Chris Dry putting them level, before Werner Kok scored in the opening seconds of the second half for a 12-5 lead.
England were then handed a huge advantage, when Kok was sent to the bin for a high tackle, and from the very next attack, James Rodwell scored in the corner, with Charlie Hayter then nailing the resulting conversion from out wide to draw his side level.
It was England who had enough in the tank to snatch victory after the full-time siren, with Norton finishing off expertly in the corner after they had been camped on the Blitzboks line for a number of phases.
England will meet Canada in the second semi-final, after a Nathan Hirayama inspired performance helped them put away Argentina 28-7.