The 22-year-old Phillips’ ingenuity as he touched down twice in the space of seven first half minutes was the highlight of what was otherwise a rather lacklustre encounter. The game’s other high point was the 50th Celtic League appearance for Matthew Watkins. He is the first Scarlet ever to reach that landmark.
Paul Warwick kicked the home side’s only points up until Matt Lacey’s late bonus point-saving try.
A poor lineout ultimately saw Connacht slip up in the race for the Heineken Cup play-off spot, as Cardiff – four points below the Irish province and now with a game in hand – remain in contention.
Returning hooker Bernard Jackman – back from Ireland squad duty – sparked an early showing from Connacht as he carried well.
But it was the Welsh – 32-17 conquerors of Munster three weeks ago – who looked the more purposeful.
Gareth Bowen’s early penalty shot slid wide but from a 26th-minute Salesi Finau breakaway, Phillips outsmarted the Irish rearguard to dive over from a quick tap penalty.
Bowen clipped over the conversion, but was wayward when Phillips ended a dogged spell of Scarlets attacking with his second, spinning past opposite number Tom Tierney for his second on 32 minutes.
The Scarlets – without regular skipper Simon Easterby – went 15-0 in front nine minutes after the restart, as a clinical Bowen punished a ruck infringement from 28 metres.
After a Matt Mostyn break, a subdued Warwick wasted no time in replying for the home side, as his right wing 30-metre penalty sailed over.
Bowen chalked up his 114th league point with another penalty, and although Warwick replied and Lacey burrowed over in injury time, a first away success since their 26-15 defeat of the Borders on the opening night of the season belonged to the Scarlets.