Worcestershire's leading run-scorer this season, Libby posted an assured 117 to steer his side to 316 for 8 in their second innings and engineer a lead of 421 going into the final day
Cheltenham (day three of four): Worcestershire 406 & 316-8, Gloucestershire 301 - Worcestershire lead by 421 runs with two second-innings wickets in hand
Jake Libby continued his prolific run of form to manoeuvre promotion-chasing Worcestershire into a position of strength on day three of the LV= Insurance County Championship match against neighbours Gloucestershire at Cheltenham.
Worcestershire's leading run-scorer this season, Libby posted an assured 117 to steer his side to 316 for 8 in their second innings and engineer a commanding lead of 421 going into the final day.
Skipper Brett D'Oliveira weighed in with a valuable 46 and helped add 114 for the fifth wicket with Libby, who now boasts 909 first-class runs at an average of 56.81 this summer, while Matthew Waite smashed a quickfire 62 from 32 balls. Paul van Meekeren took a season's best 5 for 73 to at least give Gloucestershire supporters something to cheer, and the Dutchman has now taken nine wickets in a match for the first time.
Ollie Price had earlier completed a superb career-best knock of 115, dominating a stand of 111 for the fifth wicket with his brother, Tom, who made 46. But Joe Leach, Dillon Pennington and Adam Finch finished with three wickets apiece as Worcestershire bowled the home side out for 301 to establish a first-innings lead of 105.
A declaration can be expected in the morning, after which Gloucestershire will very likely find themselves charged with the task of batting best part of three sessions to save the game. The pitch remains essentially sound, but Worcestershire found quick runs harder to come by second time around and will have been encouraged by the sight of Zafar Gohar extracting occasional turn during the final session.
Matthew Waite scored a blistering half-century [Dan Mullan/Getty Images]
Gloucestershire did their best to slow Worcestershire progress, Tom Price removing Gareth Roderick, van Meekeren accounting for Azhar Ali and Kashif Ali in quick succession and Zafar bowling Adam Hose for 21.
But Libby and D'Oliveira took charge of the situation, punishing anything short and wide from the seamers and gradually accelerating as the shine disappeared off the ball and the bowlers tired.
Libby clipped Ollie Price off his legs for two to move to his third hundred of the season and the 15th of his career from 154 balls, but D'Oliveira narrowly failed to secure his second half-century of the match, cutting to backward point and becoming the third batsman to fall to van Meekeren.
Libby's 171-ball innings came to an end shortly afterwards, the opener pulling van Meekeren to square leg. But there was still time left in the day for Waite to add to Gloucestershire's pain, the allrounder smiting half a dozen sixes in racing to 50 off 22 balls.
If Worcestershire were to give themselves a realistic chance of forcing a result, they had to fully utilise the new ball, which was taken early in the morning session. Dillon Pennington did exactly that, claiming wickets with his first two deliveries from the Chapel End, to effectively terminate Gloucestershire's prospects of building a first-innings lead.
Tom Price deflected an inside edge onto his stumps in the act of driving and was out for a 98-ball 46, Jack Taylor went for a golden duck, pinned lbw inside his crease, and Zafar then survived the hat-trick ball.
Ollie Price continued his scoring form for Gloucestershire [Harry Trump/Getty Images]
Not for the first time this season, Gloucestershire were indebted to Ollie Price, who continued to serve up defiance in spade-loads. His second first-class hundred, following hard on the heels of his first at Headingley last month, occupied 245 balls and was heralded by his 13th four, a square cut off Leach, which brought an enthusiastic Festival audience to its feet.
Since graduating from Durham University earlier this summer, the young academy product has scored 420 runs at an average of 84 and established himself as a reliable fixture in the top order. Here, he held sway for almost six hours in a marathon innings which was unexpectedly terminated when he drove Waite to short mid-on with the score on 267.
Once Gloucestershire's centurion was back in the dressing room, the tail unravelled quickly, Finch taking three wickets in eight balls from the Chapel End to wrap-up the innings in the final over before lunch.
Having contributed four runs from 67 balls in a stand of 31 for the seventh wicket with Price, Zafar went on the attack and advanced to 20 before falling to a smart catch by Josh Baker at silly mid-on. Van Meekeren was bowled without offering a shot and Matt Taylor hooked Finch for six over square leg to raise 300 and bank a second batting bonus point before succumbing to the next ball, held at short third man by Roderick.
Gloucestershire added just 89 runs to their overnight score, Worcestershire taking the six wickets they needed in 34.2 overs.