Warwickshire 198 for 3 (Yates 91, Hain 68*) trail Hampshire 539 (Stone 5-93) by 341 runs
Teenager Rob Yates fell nine runs of his maiden first-class century as Warwickshire battled hard to eat into Hampshire's huge first-innings total of 539.
Top order batsman Yates, who only signed his first professional deal last December, showed maturity which belied his age to guide his side towards the follow-on target. The 19-year-old academy graduate added a vital 142-run stand for the third wicket with fellow talented youngster Sam Hain, who collected his second Specsavers County Championship half-century of the season.
Earlier, Olly Stone had marked his return from almost seven months on the sidelines with a bone stress injury in his lower back with a five-wicket haul. Stone, who had taken three wickets on his first day of action of the season helped wrap up the Hampshire tail inside 20 overs during the morning.
Hampshire returned on 450 for 6 after an an extraordinary opening day which had seen Ian Holland and Aneurin Donald notch centuries. The bright sunshine which had shone over the Ageas Bowl made way for overcast conditions on day two, although the wicket remained flat as Hampshire added 89 more runs.
Gareth Berg lasted five overs before he was castled by Oliver Hannon-Dalby. Lewis McManus and Keith Barker, against his former county, added 60 for the eighth wicket, scoring 41 not out and 35 respectively. But the final three wickets fell for six runs as Ben Mike had Barker caught at deep square leg before Stone had Kyle Abbott lbw and Fidel Edwards bounced out to claim figures of 5 for 93.
Warwickshire's reply started poorly as Will Rhodes edged Kyle Abbott behind to leave the visitors 15 for 1 at lunch. That became 39 for 2 when Division One's highest run-maker Dom Sibley tamely chipped Abbott to cover.
With 350 runs still required to avoid the follow-on, and an uber-accurate and disciplined Hampshire bowling attack asserting plenty of pressure, Hain and Yates joined for a dogged partnership. Attacking shots came at a premium throughout the afternoon session, with the run-rate barely touching two.
Solihull-born Yates, who has played for Warwickshire since their Under-10s, was handed two lives, on 35 and 45, as plenty of runs came through the slip cordon.
Yates broke into the first team during Warwickshire's Royal London Cup campaign and hasn't been left out since. He batted patiently to reach a half-century in 144 balls, beating his previous best score of 49, and appeared on course for three figures. But he meekly fell for 91 when he struck part-time spinner Felix Organ to short midwicket.
Meanwhile, Hain passed his 3000th Championship run before moving to his own fifty in 85-balls as he ended the day unbeaten on 68. Warwickshire on 198 for 3, still 191 adrift of the follow-on and trailing by 341.