The Scarlets can still quality for the Pro14 play-offs next week after beating the Dragons, but they need Connacht to do them a favour.
The Ospreys were on the verge of victory despite George North's early red card, but Ashton Hewitt's try salvaged a draw for the Dragons.
The Dragons have added Jamie Roberts to their squad ahead of their return to Pro14 action this month.
Matthew J Watkins won 18 caps for Wales in the 2000s, before battling cancer, and his death left his former clubs "deeply saddened".
Benetton Treviso were prevented from playing at home last weekend because of the coronavirus, but returned to action by beating the Dragons.
After losing to Ospreys, Ulster bounced back by defeating Cheetahs, while Glasgow Warriors beat Dragons to move into third in Conference A.
A move to the Ospreys or the Dragons is reportedly on the cards for Rhys Webb after Toulon agreed to release him from his... Read more
It was a miserable Boxing Day for the Ospreys, as they were hammered by the Scarlets, while Cardiff Blues won the other Welsh derby.
Andrew Porter and Ronan Kelleher each crossed twice as Leinster maintained their 100 per cent record, while Edinburgh beat Dragons.
Undefeated Leinster made light work of the Dragons as Glasgow Warriors thrashed Southern Kings 50-0 on Friday.
Friday's Pro14 fixtures saw a trio of easy victories as the Cheetahs, Leinster and Connacht all won by big margins.
The Dragons believe ex-Gloucester and Worcester Warriors boss Dean Ryan is the right man to turn around their fortunes as sporting director.
Glasgow Warriors celebrated the news that head coach Dave Rennie will stay at the club by securing a famous win over Leinster in Dublin.
After over four years of consecutive away defeats in Pro14, the Dragons claimed a draw at Southern Kings.
Bonus-point wins for Glasgow Warriors and Munster mean the top two in Conference A remain three points apart.
There will be no imminent merger of Welsh regions after it was confirmed all four will stay as they are next season.