Northamptonshire 273 and 149 for 5 (Rossington 44) trail Warwickshire 573 (Hain 208, Trott 164, Chopra 53, Middlebrook 5-124) by 151 runs
Scorecard
Sam Hain became the youngest batsman to score a double century for Warwickshire in a record-breaking partnership with Jonathan Trott which pushed Northamptonshire closer to another heavy defeat at Edgbaston.
Hain became the youngest player to score a first-class century for Warwickshire when he reached three figures against Northamptonshire at Wantage Road in June and again claimed another record previously held by Ian Bell when he took a single off Andrew Hall before the home side declared on 573 for 9.
At 19 years and 57 days, Hain became the third-youngest double-century maker in the history of the County Championship after Surrey's Dominic Sibley - against Yorkshire last year - and Northamptonshire's David Sales against Worcestershire in 1996.
Hain's stand of 360 with Trott was the third-highest fourth-wicket partnership in Warwickshire's history and their best for any wicket against Northants, who reached 149 for 5 in their second innings to trail by 151 at stumps.
Warwickshire resumed on 413 for 3 and Hain reached 150 early in the day and pushed on confidently to his maiden double century from 326 balls with 24 fours and a maximum.
Trott (164) was more subdued but he played a valuable supporting role to his younger partner before he miscued a straight drive off Hall to James Kettleborough at deep midwicket which gave Northamptonshire their first wicket in 24 hours and almost 99 overs of cricket.
Hain fell after soon lunch when he was bowled around his legs lapping veteran offspinner James Middlebrook who claimed his second five-wicket haul of the season as Warwickshire went in pursuit of quick runs ahead of their declaration.
Middlebrook's wickets were deserved reward for his early persistence and accuracy as Tim Ambrose was stumped by Adam Rossington giving him the charge, Chris Woakes went lbw and Keith Barker was also stumped advancing down the pitch.
By that time Warwickshire stretched their lead of 300 and Northamptonshire soon ran into trouble at the start of their second innings on a pitch that offered early encouragement for the seamers.
Woakes celebrated his award of an England central contract by pinning Northamptonshire captain Stephen Peters lbw and knocking back Kyle Coetzer's off stump in a demanding opening spell.
There were promising cameos from Kettleborough and Rob Keogh but both fell when apparently well set. Kettleborough edged Jeetan Patel to Rikki Clarke at slip and Keogh was caught behind by Ambrose trying to withdraw the bat from a Barker delivery that was angled across him.
Rossington played positively for his 44 but was then snaffled by Hain at short leg off Patel which left Northamptonshire facing their 11th defeat, and seventh by an innings, of a morale-sapping season.
Woakes was pleased with his side's performance during the match and praised a season to remember, saying: "We are in a good position, the boys have played well all year in all formats.
"To be in the Royal London One Day Cup final next Saturday having already won the NatWest T20 Blast and to still be pushing for the County Championship at this stage of the season is credit to everyone in the dressing room.
"Obviously it looks like Yorkshire are going to win at Trent Bridge so it looks like we are now pushing for second place but no one wants to be playing for dead rubbers at this stage of the season.''
