The Vikings fielded eight debutants and looked determined to avoid a repeat of last season�s relegation battle as they caused Saints some uncomfortable moments in the persistent rain.
In the end Saints proved too strong, scoring four of their seven tries in the second half to wrap up the points. Paul Sculthorpe finished as their top point-scorer with a tally of 12 and Jamie Lyon had a pleasing debut, creating two second-half tries with kicks.
Kick-off was delayed 10 minutes due to crowd congestion but Saints wasted little time in moving ahead as Sculthorpe fed Nick Fozzard and the prop forced his way over.
Saints� indiscipline allowed Widnes to claw back four points with two penalties and the sin-binning of James Graham for holding down Jon Whittle could have cost them further. But Saints twice caught the Vikings on the break to run in two tries in the space of three minutes midway through the first half.
Ade Gardner generated the momentum for the first by carrying the ball to halfway and Sculthorpe took the ball to the line after brilliantly ducking under a tackle in taking a Long pass.
Long was impeded as he attempted to touch down and Paul Wellens made sure of the score but referee Richard Silverwood eventually awarded a penalty try for the initial offence.
The third try followed moments later as Long broke clear down the left and passed inside for Mickey Higham to race under the posts.
Sculthorpe added his third conversion but Widnes hit back again with a slick move which opened Saints up down the right to allow Aaron Moule to cross.
Rowlands converted and then traded penalties with Sculthorpe to leave the game in the balance at 20-12 the interval.
But Saints began to reassert their authority in the second half and they ground out a fourth try nine minutes after the restart.
This time there was no denying Wellens as he slid through the mud to finish a Jon Wilkin kick by the posts.
Handling conditions were becoming increasingly difficult but Lyon held onto a difficult pass after a Sculthorpe interception to set up the next try.
The Parramatta centre just did enough to cling on on the left touchline and the race to his kick downfield was won by team-mate Darren Albert.
Sculthorpe added another goal but Widnes maintained a flicker of hope as Matt Whitaker crossed and Rowlands converted to make it 30-18.
But there was little more to come from the valiant visitors. The game was all but ended as Gardner found room on the left and put James Roby over just moments after he had come off the bench.
Lyon was then involved in the thick of the action again as he charged forward and chipped over the defence for Lee Gilmour to touch down.
Sculthorpe�s sixth goal put the seal on a hard-fought win.
St Helens: 40 (20) Tries: Fozzard, Higham, Penalty, Albert, Roby, Gilmour Goals: Sculthorpe (6)
Widnes: 18 (12) Tries: Moule, Whitaker Goals: Rowlands (5)
St Helens: Wellens, Gardner, Lyon, Talau, Albert, Roby, Long, Fozzard, Higham, Anderson, Graham, Gilmour, Sculthorpe.
Cunningham, Edmondson, Bennett, Wilkin, Hardman.
Widnes: Connolly, Moule, Hughes, Emelio, Craigie, Millard, O�Neill, Cassidy, Stankevitch, Finnigan, Hulse, Whitaker, Frame.
Fa-alogo, Rowlands, Smith, Whittle, Mills.