In a dramatic climax, Gavin Henson had the chance to not only level the scores with the last kick of the game but also book the Ospreys’ place in the Heineken Cup and seriously dent their local rivals’ title ambitions.
It would have capped a remarkable comeback by the Ospreys, who had trailed Llanelli 15-3 at half-time, after wings Stefan Terblanche and Shane Williams had pulled them back into contention.
But his long range injury-time penalty drifted agonisingly wide to leave the Scarlets a point clear at the top of the table and within touching distance of the title.
Now they must now gain at least a draw at Glasgow on Friday night while Llanelli meet rivals Ulster in a title showdown at Stradey Park.
Jenkins, however, will have been encouraged by pint-sized Gareth Bowen who proved there could be life after Stephen Jones by scoring the crucial try.
The 5ft 9ins fly-half replaced France-bound Jones while he had a gash in his head stitched up and promptly slipped through for a dazzling try in first-half stoppage time.
That was after Canadian prop John Thiel gave the Scarlets the best possible start by scoring from Barry Davies’ break inside five minutes and Jones had kicked a penalty.
But the Ospreys hit back in the second half when Terblanche intercepted Scott Quinnell’s long pass to race almost the length of the field to score under the posts.
And then, with Llanelli again down to 14 men after Robin McBryde was sin binned for punching, Williams benefited from Henson’s kick through to score in the corner.
But the comeback fell short when Henson’s kick edged wide.