Northampton made a winning return to the Guinness Premiership with a 21-13 success against Worcester.
Dylan Hartley came off the bench to score the decisive try, which came after Worcester had been temporarily reduced to 14 men when flanker Tom Wood was yellow-carded for an infringement which allowed Northampton skipper Bruce Reihana to level the scores at 6-6 with his second penalty.
Northampton, who stormed through National Division One unbeaten last season for an instant return to the Premiership, had a second try when centre Jon Clarke went over in the 66th minute
Worcester, with former Australia full-back Chris Latham making his Premiership debut, finally made an attacking impression as hooker Aleki Lutui went through the home defence for a 72nd-minute try, converted by new fly-half Matthew Jones.
But Reihana's third penalty, in the 76th minute, secured a deserved victory for his side.
Sale got their campaign off to a sound start with a 14-9 victory over Newcastle.
Charlie Hodgson's early try gave Sale the lead, which they never surrendered with three penalties from Luke McAlister.
Newcastle fly-half Rory Clegg kept them in touch with two penalties and a drop-goal but it was not enough to haul back Sale.
Bath triumphed 33-20 over Bristol in the west country derby, scoring three tries to two as fly-half Butch James kicked 18 points for their first Premiership victory at the Memorial Stadium since March 1998.
That was the season when Bristol were first relegated and they started this campaign where they left the last one - with another defeat, their seventh in a row.
On Saturday, Wasps endured a torrid start to their title defence with London Irish emerging easy 26-14 winners from the season's curtain-raiser at Twickenham.
The champions' frailties at the lineout were exposed by Chris Hala'ufia and Richard Thorpe who crossed for Irish after capitalising on errors at the set-piece.
Ian McGeechan's side are traditionally slow starters - last season they left their revival later than ever - and they were off the pace and shapeless in attack.
Irish were left reeling after finishing seventh last term, a position which meant they missed out on qualification for the Heineken Cup, but their rout at Twickenham was an impressive declaration of intent.
They were a far more threatening side, showing a creative spark in attack matched by a tigerish work ethic in the loose which left Wasps living off scraps.
Australian full-back Peter Hewat finished the afternoon with 16 points, successfully completing every kick at goal, and his haul ultimately proved the deciding factor.
Final-quarter tries from Tom Rees and Eoin Reddan gave the score respectability but Hewat's boot meant the outcome was never in doubt.
In the day's other game, David Strettle took just 53 seconds to remind England boss Martin Johnson of his try-scoring prowess as Harlequins opened their campaign with a 24-21 victory over big-spending Saracens.
Strettle was dropped from the senior England squad after a difficult summer tour to New Zealand, both on and off the field, but he took less than a minute to make his mark on the new season.
Debutant fly-half Nick Evans kicked 11 points and Strettle's fellow winger Ugo Monye sauntered over for a second-half try as Quins held off a determined effort from Saracens.
Adam Powell and Neil de Kock ensured the Men in Black remained in touch but their refusal to attempt a late drop goal eventually cost Eddie Jones' men in a tight Twickenham clash.
