Leinster's defence of their Celtic League title is in tatters after they lost their fourth match on end - 18-23 to Scottish new boys Borders.
Leinster now have to win their final two matches, secure two bonus points and hope other results go their way if they are to make the quarter-finals.
Edinburgh thumped a poor Llanelli outfit 38-14, while Ulster ended Munster's unbeaten run with a 26-17 victory at Ravenhill.
Scrum-half Neil Doak, an Ireland cricket international, scored all of Ulster's points to add some spice to the Pool A table.
Neath all but confirmed a quarter-final berth with a comfortable 34-7 win over Ebbw Vale, thanks to a hat-trick of tries to fullback Gareth Morris.
Vale flanker Tyrone Morris must have broken a record when he was sin-binned 30 seconds after coming on as a replacement, in his first appearance since being red-carded against Caerphilly a fortnight ago.
Ebbw Vale captain Damien Hudd picked up the biggest accolade of the night at the 11th Principality Premiership Awards Evening held at Principality Stadium, after leading his side to the title for the first time.
Wales assistant coach Robin McBryde is predicting a tough battle against England on Sunday despite the fact they may not be considered to be at full strength. Players will be out to impress Eddie Jones which makes England a dangerous proposition, he says.
Wales U20 captain Tom Phillips and performance psychologist Dr Rich Neil explain why spending three days at Monmouth RFC has further strengthened the togetherness of the squad ahead of the #WorldRugbyU20s
Alongside Scarlets flanker James Davies and Cardiff Blues centre Cory Allen, three Wales Sevens core players have made the extended training squad for GB Sevens. Wales Head coach Gareth Williams tells WRU TV's Graeme Gillespie why Luke Treharne, Sam Cross and Luke Morgan earned selection in the initial training squad for Rio.
Wales Sevens head coach Gareth Williams tells WRU TV's Graeme Gillespie he has had to overcome a number of injuries before naming a competitive squad for this weekend's penultimate round of the World Series in Paris.