Jim Allenby and Murray Goodwin held sway in the sunshine as Glamorgan assumed the upper hand on the first day of their LV= County Championship Division Two match against Gloucestershire at Bristol.
The fifth-wicket pair staged a restorative stand of 185 in 50 overs, helping the visitors reach 318 for five by the close after they were asked to bat by Gloucestershire skipper Michael Klinger.
That decision appeared a good one when Craig Miles and David Payne took two wickets each with the new ball, but Allenby and Goodwin redressed the balance to help Glamorgan bank three batting bonus points with the prospect of more to come on the second day.
Fresh from scoring a career-best 138 not out in his last innings against Leicestershire at Grace Road, Allenby raised his second hundred inside a week to alter the complexion of the game.
He eventually succumbed to the second new ball, pinned lbw on the front foot by James Fuller having hit 105 runs from 159 balls in a knock that included 16 fours.
Goodwin and Allenby fell just short of Glamorgan's record fifth-wicket stand in matches against Gloucestershire, established by Michael Powell and James Franklin at Cheltenham in 2006.
Rather more circumspect in his approach, Goodwin was still there at stumps having struck an unbeaten 96 from 212 balls with 12 fours and added a further 48 runs with Mark Wallace, who was 31 not out.
Klinger's decision to insert Glamorgan raised a few eyebrows among County Ground regulars, but the tactic paid dividends initially as Gloucestershire's seam bowlers made the most of early moisture to rip through the top order.
Miles continued his rich vein of form when accounting for openers Ben Wright and William Bragg in successive overs after being switched to the Ashley Down Road End.
Having already claimed 20 first-class wickets at an average of 20.55 in four previous outings this season, the 18-year-old academy product further impressed on a flat County Ground pitch.
Offering his team-mates an object lesson in line and length, Miles induced Wright to prod defensively at a ball outside off stump and offer a regulation catch to Gareth Roderick behind the stumps.
Bragg succumbed in Miles' next over, pushing tentatively outside off stump and directing a thick-ish edge to Dan Housego at gully for 23.
Payne's left-arm swing ensured the home side made further inroads while the shine was still on the ball, former Gloucestershire overseas batsman Marcus North and Stewart Walters departing either side of lunch.
Australian North was squared up by a ball that came back in and caught at the wicket having contributed just four runs, while the aggressive Walters fell to a poor shot.
The former Surrey batsman had scored 28 when he flashed at a wide delivery from Payne and was held by the dependable Roderick.