Northampton Saints 23 Llanelli Scarlets 28
Northampton's Heineken Cup hopes are already hanging in the balance after a 23-28 defeat at home to Llanelli Scarlets.
It was the Saints' second loss in as many games following the first round defeat to Munster and they can have no complaints about the result.
Saints were forced to play catch up rugby from the second minute when Liam Williams hacked on scrum-half Gareth Davies's pass back inside and re-gathered to score. Rhys Priestland converted.
Ryan Lamb pulled three points back for Saints shortly afterwards when the Scarlets were penalised for not rolling away at the tackle area.
But Nigel Davies' side responded immediately, flanker Aaron Shingler diving in at the corner straight from the re-start. Priestland again supplied the extras.
Fly-half Lamb landed his second and third penalties as the Welshmen found themselves under increasing pressure.
However a mistake under the high ball from full-back George Pisi - a late deputy for Ben Foden - gifted the Scarlets their third try, scored by Matt Gilbert and again improved by Priestland, for a shock 21-9 interval lead.
On the hour, Scarlets flanker Jon Edwards was sin-binned by referee Peter Fitzgibbon for an infringement at the breakdown, but Lamb could not take advantage from the resulting penalty. His kick struck the upright and fell kindly for Saints, but a dropped pass in midfield by England wing Chris Ashton led to Scarlets' bonus-point clinching try.
Pisi then muscled over from close range to partially atone for his earlier error and Tom Wood raced home with a few seconds left on the clock to hand Saints a losing bonus point, which could prove crucial in the final shake-up if they can win their four remaining games.