Glamorgan opener Nick Selman followed his match-winning century against Durham at Swansea last month with another hundred in the Specsavers County Championship match at Chester-le-Street.
But Durham’s Chris Rushworth hit back with the second new ball, grabbing three wickets to finish with five for 40 as the visitors slipped from 182 for three to close the first day on 221 for seven.
Having elected to bat in baking heat, Glamorgan ground along all day, losing only one wicket in each of the first two sessions in reaching 147 from 66 overs.
Selman spent 249 balls over his hundred, getting there by inside-edging Rushworth for his 13th four. Three balls later he was lbw for 103.
Off-spinner Ryan Pringle conceded only 23 runs in 19 overs as Durham maintained their accuracy, with the other two wickets going to academy seamer Matty Potts in his second appearance.
Despite a minute’s silence for the London fire victims at 11am, and a drinks break at noon, Durham got through 33 overs in an attritional first session.
Jacques Rudolph fell in the seventh over when Rushworth was rewarded for an excellent spell by clipping the left-hander’s off bail.
Andrew Salter, promoted to three in the absence of Will Bragg, cut and pulled Barry McCarthy for two fours but was otherwise restrained. He departed for 25 when he pushed forward and edged Rushworth to wicketkeeper Stuart Poynter to end a stand of 66 in 34 overs.
Colin Ingram also made a cautious start but began to flourish when he drove Pringle through the covers then cut him for another four. He fell for 33 when Potts moved one away to have him caught behind.
When Rushworth took the new ball his fourth delivery swung in to take out Aneurin Donald’s off stump. Then balls which nipped back had Selman and David Lloyd lbw, although neither seemed happy with the decision.
Potts took the final wicket of the day when wicketkeeper Tom Cullen, handed his debut after Chris Cooke took a blow on the head in practice, was well caught at second slip by Pringle.
Selman said: “It was tricky against the new ball and Chris Rushworth is a quality bowler. We didn’t set out to score that slowly, but the pitch kept doing a bit and they bowled well to their fields and kept up the pressure.
“I need to be more consistent and I think I’m getting there. Once I get to 20 or 30 I work hard to try to make it a big one.
“It was disappointing to lose those wickets at the end but if we can push on towards 300 we will hope to bowl as well as they have done.”