Mako and Billy Vunipola were influential as Saracens launched their Aviva Premiership title challenge by thrashing London Irish 42-20 at Twickenham.
The wrecking-ball England forwards played their first game together for Saracens, Mako breaking tackles at will after arriving as a try-scoring substitute and Billy rampant throughout.
Billy arrived from Wasps to join his elder brother during the summer but Mako, who enjoyed a successful British and Irish Lions tour to Australia, was the more destructive.
England Under-20 hooker Jamie George, deputising for the suspended Schalk Brits, crossed twice in the first half to help Saracens establish a comprehensive 21-10 half-time lead that was beyond overwhelmed Irish.
The try-scoring bonus point appeared to have eluded the Premiership title contenders, but the outstretched arm of Chris Ashton delivered the fifth point in the final move of the game.
Owen Farrell, commanding throughout, kept the scoreboard ticking over with 22 points to ensure the outcome was never in doubt.
Fears that Irish face a long season spent battling relegation were confirmed by a result that suggests they will struggle following their summer exodus of players.
Their highlight was supplied by England wing Marlon Yarde, who built on his fine summer tour to Argentina by cutting short treatment for cramp to join the end of a backs move that finished with him touching down.
Saracens' superiority was evident from the start as Irish were pinned back on their goalline with George running on to a flat ball from close range and easily shrugging off a feeble tackle by Sailosi Tagicakibau.
Farrell kicked the conversion to add to an earlier penalty, but the Exiles responded with a fine passage of play sparked by fly-half Ian Humphreys' smart offload to full-back Topsy Ojo.
Humphreys landed three points, number eight Jon Fisher burst from the base of a scrum and Ojo showed his strength with a determined run as Saracens came under pressure.
Irish almost profited from a dreadful pass by Brad Barritt that went straight to Tagicakibau, but they soon trailed 13-3 after Farrell slotted a second penalty.
Ashton was held up over the line, but Saracens' second try followed shortly after when George and scrum-half Richard Wigglesworth combined at a line-out.
They swapped passes with George easily rounding Humphreys to dart over as the Exiles' defence was exposed once more.
Irish responded brilliantly with blindside flanker Kieran Low taking David Paice's pass and running half the pitch to crash over, evading tackles en route to the line.
Humphreys converted, but Farrell was doing a marvellous job of keeping the scoreboard ticking over as he slotted penalties either side of half-time.
Yarde was being fed more ball but with the Exiles' scrum struggling, he was swimming against the tide.
The rampaging Mako Vunipola was a thorn in Irish's side and in one move he secured the turnover before popping up on the final pass to power over as Saracens celebrated a third try.
Lions prop Matt Stevens was sin-binned for a shoulder charge and Irish capitalised on the extra player through Yarde as a pre-planned scrum move paid off.
Saracens were guilty of a lack of ambition in the closing stages, but finally they secured the fifth point courtesy of a superb finish by Ashton in the final act of the game.