Hampshire are on the back foot as Glamorgan enjoyed the better of day three of their County Championship clash.
John Glover led some late Glamorgan batting aggression to put his side in a dominant position at the Ageas Bowl.
Glover, who had hit only one previous half-century in his career, struck eight fours in an unbeaten 51.
His captain Mark Wallace declared with Glamorgan 129 ahead at 478 for nine in their first innings.
Hampshire openers Jimmy Adams and Michael Carberry both fell before the close, with Liam Dawson 34 not out left to battle on as the hosts closed on 115 for two, still 14 behind.
Both sides are in desperate need of a win, with Glamorgan having won only once in 10 division two fixtures and Hampshire only twice.
Glamorgan started the day trailing Hampshire by 123 runs.
But they soon made up the deficit.
Chris Cooke (92) and Jim Allenby (62) made their fifth-wicket stand worth 127.
Sohail Tanvir dismissed Allenby and Chris Wood removed Cooke.
But Hampshire were punished further as the Glamorgan lower order hit out and the declaration came with number nine batsman Glover have done plenty of damage.
The hosts then lost Adams for just 10, deceived by Cosker’s turn, and Carberry fell for 62, after a second-wicket partnership of 82 with Dawson.
Carberry at least had the satisfaction of reaching 10,000 career runs in first-class matches.