The Scarlets, who fielded 13 internationals, won 26-17 against a Saracens side which showed 14 changes to the team which won at Bristol on Wednesday.

Jones said: "I'm not pleased with the result. It's a game we should have won - and should have won well. There are some promising things there but there were some silly, little errors. We turned the ball over at the set-piece and the breakdown, made some uncharacteristic handling errors and didn't have enough motion on the ball.

"I'm disappointed with that but there's a foundation there for Saracens going forward and that's very important for us to be a successful club.

"There were six or seven guys under the age of 20 that played today and a lot of those have good futures if they work hard."

One of those prospects is Owen Farrell, who became the youngest player to appear in a top-flight game when he replaced another youngster, centre Alex Goode, in the 67th minute.

At 17 years and 11 days, the son of Andy Farrell - the injured Saracens centre and former Great Britain rugby league captain - beat Danny Cipriani's record by 36 days.

Jones said: "He is one of a group of young kids coming through. He's very mature, he's got a very serious attitude and is desperate to make it.

"He understands the game for a young kid and has a good appreciation of what's going on around him."

Jones was also impressed by the try-scoring performance of England Under-20 international Noah Cato.

"We'd like to think by the end of the season he's playing Premiership consistently," added director of rugby Jones.

Scarlets coach Nigel Davies, who took charge of the Welsh side during the summer, had a similar mixed reaction.

"The win was really important to us for lots of different reasons," said Davies, whose side conceded a total of 66 points in defeats by Edinburgh and Glasgow in their last two Magners League games.

"This competition is something we have targeted and to start with an away win is great."

However Davies was critical of the display by his virtually full-strength side.

"In terms of performance there was a lot missing there," he said.

"We're a new group of people and there's a lot of work to do. In the second half the defence went up a couple of notches - but it needed to."

Overall, Davies is satisfied to be going into next Saturday's Heineken Cup opening clash with Harlequins on the back of a much-needed victory.

"It's going to be a really tough encounter. I've seen Harlequins and they're playing some good rugby," Davies said.

"They have a steely edge about them which they probably haven't had before so we are going to have to work on things this week and make sure we improve."