Saracens crashed to a 26-17 defeat at home to the Scarlets in the EDF Energy Cup this afternoon at Vicarage Road.

Despite scoring first-half tries through the excellent wing Noah Cato and Francisco Leonelli, the hosts were undone by the Welsh outfit after they responded through efforts from David Lyons and Kees Meeuws. With only the winners from each group progressing to the semi-finals, it leaves Sarries' hopes hanging by a thread with games to come against Bristol and Northampton Saints.

Eddie Jones made 14 changes, from the team against Bristol, for the opening match in the competition after a busy period of two games in the last week. Sarries' director of rugby selected a side with plenty of youngsters including England Under-20 star Cato and Don Barrell. He also handed a full debut to 6ft 7in second row Harry Spencer and from the bench, Jackson Wray, Hayden Smith, Alex Walker, Mickey Wilson and Owen Farrell. The son of the former Great Britain rugby league star became the youngest player to appear in the EDF Cup at the age of 17 and 11 days. Moses Raulani was given the captaincy in the absence of Steve Borthwick and Andy Farrell. The Scarlets were virtually at full strength as they tried to rediscover their form after successive defeats in the Magners League.

The Men in Blank squandered an early opportunity to put points on the board when fly half Gordon Ross missed a penalty in the first minute. But the Welsh opponents were also off target with their first attempt as Stephen Jones sent his penalty wide of the posts.

But the Scarlets opened the scoring in the eighth minute when pressure from the scrum by the five-metre line forced them over and Lyons grabbed the first try of the match. Jones easily converted to hand the visitors the early advantage.

Saracens drew level within four minutes after an excellent attack brought a try for Leonelli. Rauluni picked up the ball in midfield, passed to Alex Goode, and it was laid off to the Argentine to run through for the score. Ross added the conversion to tie the game at 7-7.

Cato dazzled the sparse crowd after 17 minutes with a fine example of his blistering pace. The wing kicked the ball over the defence and ran onto it before another kick saw him just run out of room, with a try beckoning, as he crashed into the advertising boards.

But it took only two minutes for the 20-year-old to get on the scoresheet. Rauluni, Ross and Goode combined before releasing Cato and his speed and strength proved too much for the away side as he found the tryline. Ross' conversion extended the home side's lead after a dominant spell of pressure.

Jones kicked over a penalty after 24 minutes to bring the Scarlets within four points of Saracens. They almost scored their second try after 28 minutes but Martin Roberts knocked on after a decent break down the right.

Sarries conceded another penalty on 32 minutes for obstruction and Jones made no mistake with a comfortable strike between the posts. The Scarlets wasted the chance to regain the lead, five minutes before the break, when Jones fired wide with yet another penalty. But more indiscipline from the hosts, when Goode was caught holding on, enabled Jones to kick the visitors into a slender lead at the break.

The Men in Black did not have to wait long to go back in front as a penalty by Ross from inside his own half helped fire them into a 17-16 lead two minutes into the second half. But the Scarlets took full advantage of a scrum by the five-metre line as their pressure, despite desperate defending by Sarries, resulted in a try for New Zealand forward Meeuws. Jones' conversion handed them a six-point lead over the home side. Gavin Thomas thought he had extended their lead but his try was disallowed for offside.

Saracens were reduced to 14 men after 62 minutes when Dan Scarbrough was sinbinned for hauling down Gavin Evans. And Jones converted the resulting penalty making it 26-17 to the Scarlets.

But the visitors also lost a man when Roberts was shown a yellow card for knocking the ball out of Rauluni's hands.

Sarries tried desperately to get back in the match but they were unable to break down the resolute opposition as they got off to a losing start in the cup.

Saracens: Scarbrough, Thrower (Penney, 65), Leonelli, Goode (Farrell, 63), Cato, Ross, Rauluni (Wilson, 78); Lloyd (Mercey, 78), Cairns (Walker, 78), Mercey (Visagie, 52), Chesney, Spencer (Smith, 58), Barrell, Saull (Wray, 57), Skirving.

Scarlets: C Thomas, Jones, King, Evans, Brew, Jones, Roberts (Martens, 75); I Thomas (John, 73), Rees (Owens, 76), Meeuws, Cooper (Macleod, 66), Maling, Easterby, G Thomas, Lyons.

Scoring: 0-5, 0-7, 5-7, 7-7, 12-7, 14-7, 14-10, 14-13, 14-16 HT 17-16, 17-21, 17-23, 17-26.

Referee: James Jones Attendance: 6,068.