Moeen Ali's first century in the County Championship for nearly two years steered Worcestershire into a strong position in their Division Two clash with local rivals Gloucestershire at New Road.
Having bowled out their neighbours for 234, Worcestershire moved into a lead of 68 with Moeen - dropped at mid-off on 99 by Liam Norwell - closing the second day on 122 not out in a total of 302-3.
While Moeen was all flair and flicks, with 18 fours and three sixes, the diligent Matt Pardoe grafted for nearly five hours for 89, the highest of seven half-centuries so far in his championship career.
Their partnership of 173 in 52 overs built on the advantage secured by Alan Richardson's first-day return of 8-37, the best championship bowling for the county since Zaheer Khan took nine wickets against Essex in 2006.
After rain in the morning had cost an hour's play, Gloucestershire's seamers were unable to match Richardson's destructive performance when Daryl Mitchell and Pardoe resumed their overnight partnership of 65.
The opening pair moved on to 90 before Mitchell, having hit 10 fours, went for 63, carving a ball from Norwell to Benny Howell at point.
If Gloucestershire hoped this would put them back in the game, they were quickly disappointed as the entertaining Moeen revealed his full repertoire in reaching three figures from 130 balls.
In a partnership of left-handed batsmen, Pardoe had a different role to play and he carried it through as Worcestershire would have wanted when pushing him up the order in place of last year's overseas player, Phil Hughes.
Tall and watchful but always quick to punish the bad ball, he hit seven fours in reaching 50 for the second match in a row at New Road and he added five further boundaries before the new ball gave Gloucestershire a lift late in the day.
In the third over, James Fuller bowled Pardoe, before Thilan Samaraweera became a leg-before victim for Craig Miles from the ninth ball he faced.
The final session was twice interrupted by rain and in all 27 overs were lost to the weather.