Harri Keddie's late try earned Newport Gwent Dragons a dramatic 17-14 win over Wasps in the Premiership Sevens final at The Stoop, Twickenham.
The Welsh region won the Welsh round earlier this month.
And they made history by becoming the first Welsh team to take the cross-border finals title with Elliot Frewen named player of the tournament.
Dragons beat Sale 26-10 and 2014 winners Gloucester to reach the final.
Scarlets fell 33-12 in the semi-finals to Wasps, having beaten Newcastle 31-26 in their opening game.
Newport Gwent Dragons 26-10 Sale Sharks
Gloucester Rugby 31-26 Harlequins
Wasps 33-5 Exeter Chiefs
Newcastle Falcons 26-31 Scarlets
Sale Sharks 45-24 Harlequins
Newport Gwent Dragons 19 Gloucester Rugby 14
Exeter Chiefs 14 Newcastle Falcons 12
Scarlets 12 Wasps 33
Plate final: Sale Sharks 19 Chiefs 26
Final: Newport Gwent Dragons 17 Wasps 14