A stirring second-half comeback took the Scarlets to the brink of victory in a see-sawing west Wales derby, only for a try by Wales skipper Jac Morgan to inflict more late heartache.
Having trailed 17-5 at half-time and on the wrong side of the officials at the set-piece, it looked bleak for the men from Llanelli.
But tries from Taine Plumtree and Blair Murray turned the game on its head in the second period, only for player-of-the-match Morgan’s intervention to secure the spoils and the URC Welsh Shield for the hosts.
Inspired by some dazzling running from the likes of Macs Page, Joe Roberts and Murray, Scarlets created plenty of opportunities – notably when the quick-stepping Page was halted by a desperate ankle tap with the line beckoning in the second half.
But for the third successive URC fixture, the Scarlets were left to rue what might have been.
It was the home side who were up and running early, courtesy of Wales fly-half Dan Edwards who burst through for the opening try after just six minutes – a score he also converted.
Scarlets’ response was strong and swift and after Eddie James had punched a hole in midfield, No. 8 Fletcher Anderson did more damage before second row Max Douglas touched down beneath a pile of bodies.
In the opening quarter, Scarlets were causing the Ospreys defence plenty of problems with their deire to keep the ball alive and crafted a chance midway through the half only for the ball to be spilled with the whitewash beckoning.
The remainder of the half, though, belonged to the home side, who took a grip on the scrum battle, forcing penalty after penalty against the visitors.
Edwards extended the home side’s lead with a three-pointer from straight in front on 32 minutes, then Scarlets were reduced to 14 men when Roberts saw yellow for a dangerous tackle.
The Ospreys took full advantage with Edwards sneaking over blindside for his second from and the Wales 10 nailed the conversion to make it 17-5.
To compound the Scarlets’ misery, Kemsley Mathias saw yellow on the stroke of half-time following a series of scrum penalties against the visitors.
Hawkins reduced the arrears for the 13-men Scarlets with a well-struck penalty from halfway two minutes after the restart and it triggered the best period of the match for the visitors.
Ospreys were reduced to 14 men when Aussie lock Ryan Smith was sin-binned for a slowing down offence at the breakdown after a brilliant counter from deep by the outstanding Page and Roberts – who was straight back into the fray after his 10 minutes on the sidelines.
The Scarlets made the pressure pay when flanker Plumtree stretched over from a tap penalty move. Hawkins was wide with the conversion, but the visitors were back in it at 17-13.
The razor-sharp Page was then denied a brilliant solo score by a last-ditch ankle tap from Owen Watkins when he looked like he had the beating of the Ospreys defence.
However, the Scarlets stunned a packed Brewery Field when they conjured up a third try out wide for Murray following a rampaging run from replacement Josh Morse and sharp hands from that man Page. Hawkins landed the conversion.
Ospreys hooker Sam Parry was held up from a tap move on the hour mark, then scrum-half Dane Blacker scythed open the Ospreys defence only for the home side to get the penalty decision on their line.
The Scarlets led 20-17 up until the 75th minute, but Morgan, in his final home match for the Ospreys before his move to Gloucester, managed to muscle his way over the whitewash and with the clock ticking into the red, another scrum penalty led to Edwards hammering home the final nail with the last kick of the match.
Ospreys – tries: D. Edwards (2), J. Morgan. Cons: Edwards (3). Pens: Edwards (2)
Scarlets – tries: M. Douglas, T. Plumtree, B. Murray. Con: J. Hawkins. Pen: Hawkins