Prop Adam Jones says the Scarlets are favourites to make the final Pro12 play-off place ahead of the Ospreys.
The Scarlets and the Ospreys, the reigning champions, have been fighting it out for the fourth and final spot for the play-off semi-finals.
Scarlets recorded a 24-6 win over the Cardiff Blues,
Ospreys suffered a 35-17 defeat to Glasgow
in the last round of games.
"It's obviously in their hands now," said Wales and Lions prop Jones.
Simon Easterby's Scarlets are now in the driving seat for the final play-off spot and are in fourth place, with a four-point cushion between the Ospreys in fifth place with one game of the regular season to play.
The Scarlets host the Italian outfit Treviso at Parc Y Scarlets and the Ospreys travel to face former Heineken Cup champions Leinster on Friday, 3 May.
"Obviously we can [reach the play-offs] but we all know the way the Scarlets are playing at the moment that it is a tough game for Treviso," said Jones.
"To go there and a beat the Scarlets or restrict their points... it's obviously in their hands now.
"They are the side which came out with the good wins against the Blues and Glasgow and we bottled it.
"We weren't particularly good against Glasgow, but fair play to the Scarlets they have played better than us this season."
Meanwhile, Ryan Jones, who has been
sidelined with a shoulder injury back in March
, has targeted a return for the Ospreys in their final game of the regular Pro12 season against Leinster in Dublin.
Jones was ruled out of the Six Nations title decider against England in Cardiff after he was forced to leave the field in the 48th minute at Murrayfield after injuring his shoulder in
Wales' 28-18 win over Scotland.
"It is the realistic opportunity to get back to playing and is the one we earmarked all along," said Jones.
"We have a must-win game against Leinster in Dublin and then we have to rely on Treviso to help us out a bit down west
"We have a chance and in sport that is all you ever need.
"You see it time and time again and that is why we turn up and all watch it. Everyone loves an upset."