Ulster 31 (11)
Tries: Humphreys, Steinmetz, Bartholemeusz
Cons: Humphreys 2
Pens: Humphreys 4
Scarlets 16 (16)
Tries: Daniel
Cons: S Jones
Pens: S Jones 3
Ulster started their defence of the Magners League title with a comeback victory at Ravenhill on Saturday night.
A David Humphreys try helped Ulster into a deserved early lead but the Scarlets hit back through the boot of Stephen Jones and Darren Daniel's try.
The Welsh visitors led 16-11 at the break but Ulster dominated the second half to come out easy winners.
The impressive Humphreys added two penalties while Paul Steinmetz and Mark Bartholemeusz scored converted tries.
Ulster began like champions and their early pressure was rewarded with Humphreys kicking a penalty before claiming a 10th-minute try after Neil McMillan charged down a Stephen Jones clearance.
Mark McCall's side were totally dominant before the Scarlets launched their comeback with Jones' first penalty on 13 minutes.
Another Jones penalty was followed by Daniel's converted touchdown on 22 minutes, with the teenage winger chipping into space and outpacing Andy Maxwell to collect and go over.
The balance of the game had swung completely and Jones added another three points to give the visitors a 16-8 advantage.
Humphreys gave his team a much needed lift with a penalty four minutes from the break.
Ulster started the second half just like the first and Humphreys reduced the gap to two points with a 44th minute penalty.
The former Ireland fly-half then missed a three-point chance but made no mistake with another on 58 minutes as Ulster regained the lead.
Ulster were in control and Humphreys' pin-point chip allowed Steinmetz to slide over for a converted try after 65 minutes.
Stephen Jones missed a vital penalty before Ulster wing Mark Bartholemeusz intercepted with two minutes left and ran almost the length of the field for a converted try.
Ulster fly-half David Humphreys:
"We started well but for 25 minutes we didn't touch the ball.
"There were some harsh words said at half-time and the main thing was that we had to up our physical intensity around the breakdown, where the Scarlets had blown us away.
"We showed in the second half we can produce a big performance when required."
Ulster: B Cunningham; M Bartholemeusz, P Steinmetz, P Wallace, A Maxwell; D Humphreys, K Campbell; J Fitzpatrick, P Shields, T Court, J Harrison (capt), T Barker, S Ferris, N McMillan, R Wilson.
Replacements: N Brady, D Fitzpatrick, M McCullough, K Dawson, P Marshall, K Maggs, S Young.
Scarlets: Martyn Thomas; Dafydd James, Regan King, Gavin Evans, Darren Daniel; Stephen Jones, Dwayne Peel (capt); Phil John, Matthew Rees, John Davies, Lou Reed, Scott Macleod, Inoke Afeaki, Gavin Thomas, Nathan Thomas.
Replacements: Craig Dunlea, Ken Owens, Adam Jones, Alix Popham, Clive Stuart-Smith, Ceiron Thomas, Matthew Watkins.
Referee: Andy Ireland (Scotland)