Cardiff Blues were in sensational form, running in five tries in a 35-23 win over Welsh ricals the Scarlets in the LV= Cup on Saturday.
The Blues scored three in the space of 12 minutes after half-time, when they had trailed 17-7 and must now wait on Sunday results to see if they have made the semi-finals.
Scarlets went into the match just needing a bonus point to reach the last four but, like the Blues, will now have to sweat on the result of the match between Harlequins and Newcastle tomorrow.
Scarlets welcomed back Regan King for his first start in 11 months since seriously injuring his hamstring.
And the Blues fielded four New Zealanders - Ben Blair, Paul Tito, Xavier Rush and Casey Laulala - as well as Deiniol Jones and former Wales captain Gareth Thomas.
The fact that the game remained scoreless until the 29th minute was in part due to some dreadful tactical kicking from both sides.
But there had been chances to score; Blues flanker Sam Warburton charged down a kick from Dan Evans but could not gather the loose ball, Scarlets Lee Williams looked to pass when he could have scored in the right corner, and at the other end Williams pulled off a great try-saving tackle on Thomas just yards from the line.
The deadlock was eventually broken by Rhys Priestland, who forced his way over from five metres out after a concerted period of Scarlets pressure.
The Blues should have replied straight away but Ceri Sweeney dropped the ball under the posts. His blushes were spared on 34 minutes when Tom Shanklin forced his way over to level things at 7-7.
But it was all Scarlets for the rest of the half as they scored two tries in the space of four minutes to lead 17-7 at half-time.
First Williams made up for his earlier effort by winning the race over the line after he kicked ahead, and after a strong scrum David Lyons squeezed in.
After the break it was all Blues and they raced into a 28-17 lead with three tries,
two for Laulala.
His first came from a scrum on the 22 and six minutes later he ran in from 70 metres after intercepting a pass.
The Blues' purple patch was complete when prop Taufa'ao Filise burrowed over for the bonus-point try.
The Scarlets stopped the rot with two Priestland penalties, but the losing bonus point was ripped out of their grasp by Tito's try two minutes from time.
For the Scarlets:
Tries: Priestland, Williams, Lyons
Pens: Priestland 2
For the Blues:
Tries: Shanklin, Laulala 2, Filise, Tito
Cons: Blair 5
Scarlets: 15 Daniel Evans, 14 Lee Williams, 13 Gareth Maule, 12 Regan King 11 Andy Fenby, 10 Rhys Priestland, 9 Tavis Knoyle, 8 David Lyons (capt), 7 Josh Turnbull, 6 Rob McCusker, 5 Damian Welch, 4 Lou Reed, 3 Deacon Manu, 2 Ken Owens, 1 Phil John.
Replacements: 16 Iestyn Thomas, 17 Emyr Phillips, 18 Rhys Thomas, 19 Vernon Cooper, 20 Johnathan Edwards, 21 Martin Roberts, 22 Daniel Newton 23 Joe Ajuwa.
Cardiff Blues: 15 Ben Blair, 14 Gareth Thomas, 13 Casey Laulala, 12 Tom Shanklin, 11 Dafydd James, 10 Ceri Sweeney, 9 Darren Allinson, 8 Xavier Rush, 7 Sam Warburton, 6 Maama Molitika, 5 Paul Tito (capt), 4 Deiniol Jones, 3 Gary Powell, 2 T Rhys Thomas, 1 Taufa'ao Filise.
Replacements: 16 Rhys James, 17 Scott Andrews, 18 Ian George, 19 Scott Morgan, 20 Andries Pretorius, 21 Tom Slater, 22 Sam Norton-Knight, 23 Chris Czekaj.
Referee: Greg Garner (England)