Glamorgan fast bowler Graham Wagg says they could face a difficult final day against Northants as they look to press home their advantage in Cardiff.
The visitors finished day three on 163-4 following-on in their second innings, still 51 runs behind, after Wagg had removed both openers cheaply.
"It was a fantastic effort as the wicket got better and better throughout the day," Wagg told BBC Wales Sport.
"But it's going to be a long hard toil again for us."
Rob Newton with 89 not out provided the main resistance for Northants after they had folded to 157 all out in their first innings.
Wagg is expecting the victory bid to be similar to the closing stages against Essex, when Glamorgan had to bide their time on a placid wicket on the final day.
"There's a bit of spin there for young Salts [Andy Salter], who bowled extremely well in the first innings for his three wickets," said Wagg.
"It's going to be hard to get the breakthroughs but as soon as we do get the breakthroughs, we can go bang, bang, bang and get another three wickets on board.
"It's been very difficult especially for the seamers bowling at the Taff End, so it's going to be a long hard slog once again."
Glamorgan have earned seven bonus points from the match compared with Northants' three, having started two points behind the Midlands county in the table.
The visitors also face a potential deduction for a slow over rate unless they manage to improve their situation on the final day.