Glamorgan fought back to gain a lead of 141 on day three of their LV= County Championship match against Sussex, closing on 499/5.
A record fourth-wicket stand between Kiran Carlson (187*) and Marnus Labuschagne (138) saw the Welsh county score 381 runs in the day.
Carlson remains unbeaten with Chris Cooke (12*) overnight, with all results still possible on the final day.
"It's been a very enjoyable season so far, I think we've played some great cricket," said Labuschagne.
"For me personally, it's a bit underwhelming not being able to put us in a situation where we can potentially win the game on day four.
"I think Kiran and Chris and the boys to come can certainly put them in that position but I thought Kiran and I had them there and I think we could have put a lot of pressure on them and got a result."