Centuries by skipper Tony Penberthy and Gerard Brophy helped Northamptonshire to gain the upper hand against Glamorgan at Cardiff.

Penberthy made 120 not out and Brophy 110 - his maiden Championship century - as Northants reached 409 for eight to lead by 61.

Resuming on three without loss in reply to Glamorgan's 348, Northants scored at a healthy rate with Rob White particularly severe on anything loose.

But Glamorgan made their first breakthrough with the total on 34, Mark Powell (seven) glancing a legside catch off Thomas to 'keeper Mark Wallace.

Northants lost wickets at regular intervals before lunch and David Sales (14) was the next to go on 61, getting an inside edge to an Andrew Davies delivery and playing on.

Jeff Cook hit three fours and a six in a breezy 23 before he played a loose drive off seamer David Harrison and was caught by Wallace.

With the total on 125, Glamorgan then removed the dangerous White, bowled by Thomas.

White (69) hit Thomas for 16 runs in five balls before going for one big hit too many, pulling a short ball straight into the hands of Adrian Dale.

White faced only 62 balls, hitting eight fours and three sixes.

Thomas struck another blow on the stroke of lunch when Matt Cassar (eight) failed to keep down a hook and spooned a catch to Jonathan Hughes at square leg.

Northants were left facing the prospect of a substantial first-innings deficit and even the possibility of being forced to follow on.

But Penberthy and Brophy combined to frustrate the Glamorgan attack throughout the afternoon session.

Between lunch and tea, they put on 137 in 39 overs with Brophy playing the dominant role.

He went on to reach 110 out of a stand of 174 before he attempted a big legside hit off Harrison and miscued to skipper Robert Croft.

Penberthy saw Tobin Bailey and Carl Greenidge depart cheaply, but he completed a fine ton and batted through to stumps, sharing an unbroken stand of 54 for the ninth wicket with Mathew Inness (25 not out).

Glamorgan: M P Maynard, M A Wallace (Wkt), D L Hemp, M J Powell, A Dale, J Hughes, R D B Croft (Capt), S D Thomas, D S Harrison, A P Davies, D A Cosker.

Northamptonshire: R A White, M J Powell, D J G Sales, J W Cook, M E Cassar, A L Penberthy (Capt), T M B Bailey (Wkt), G L Brophy, C G Greenidge, M W H Inness, J F Brown.