Saracens started their English Premiership title defence with a 35-3 win over the Worcester Warriors, while there were also victories for Bath, Harlequins, Newcastle and Leicester.
Saracens held a slender 6-3 lead after a low-key first half as both sides favoured the cautious approach.
The second half was the complete opposite as Sarries took charge of proceedings to wrap up a bonus-point victory.
Hooker Jamie George crossed for the first try soon after the break, before debutants Alex Lozowski (flyhalf) and Schalk Burger (flank) drove home the advantage with further scores. And in the 78th minute, replacement scrumhalf Ben Spencer left three tacklers in his wake to go over for the bonus-point try.
Credit will go to the Saracens attack, but their defensive effort was excellent in equal measure as they kept Worcester scoreless in the second stanza.
Meanwhile, the Leicester Tigers grabbed two late tries to upset Gloucester 38-31 in the opening match of the competition. Bok winger JP Pietersen made his debut for the Tigers and scored their second try at Kingsholm.
In other results, the Newcastle Falcons – who narrowly escaped relegation last season – stunned the Sale Sharks 19-17, Bath caused a big upset when they beat the Northampton Saints 18-14, and Harlequins struggled past newcomers Bristol to claim a 21-19 victory at Twickenham.
Round 1 results:
Saracens 35 Worcester Warriors 3
Leicester Tigers 38 Gloucester 31
Newcastle Falcons 19 Sale Sharks 17
Bath 18 Northampton Saints 14
Harlequins 21 Bristol 19