Captain Mark Pettini scored an unbeaten 87 as Essex held the edge on the second day of their crucial Division Two clash against Glamorgan at Cardiff.

Essex ended the day on 277 for seven, a deficit of 34 on Glamorgan's first innings of 311 all out.

Before the start of play Glamorgan captain Jamie Dalrymple handed opener Gareth Rees his county cap following his 122 on the opening day.

Surprisingly, Dalrymple then handed medium pacer Jim Allenby the new ball ahead of strike bowler Garnett Kruger. The experiment lasted four overs as Alastair Cook and John Maunders made a confident start.

On the benign surface there was little encouragement for Glamorgan's pace battery and within an hour Robert Croft was into the attack.

Cook had reached 27 when he should have been stumped by Mark Wallace off Croft after dancing down the pitch.

The England left-hander made the most of his let-off and just before lunch reached his half century from 96 balls.

But at the start of the afternoon session Croft changed the complexion of the Essex innings with a burst of three for eight from 14 balls.

First he trapped Maunders leg before and two overs later claimed two wickets with consecutive balls. The first of those was the prize wicket of Cook, who top-edged an attempted sweep right down the throat of Allenby at mid-wicket, before Westley was adjudged lbw.

The third wicket was Croft's 50th first-class victim of the summer.

So, from 98 for nought Essex suddenly found themselves 107 for three.

In the next over Croft should have had a fourth wicket but Pettini was put down at slip on 22. The Essex captain had reached 34 when he was put down again, this time by Dalrymple at leg slip off Croft.

Pettini put on 64 with Matt Walker, who became the fourth Glamorgan wicket when he gave a simple bat-pad catch to Rees at short leg as Essex were 171 for four.

Pettini reached an 82-ball half century as Essex reached tea at 194 for four.

But he lost James Foster shortly after tea, trapped in front by Allenby, before Cosker broke through twice to remove Graham Napier, caught at slip by one that turned appreciably, and Tim Phillips.

Pettini and David Masters survived the final 10 overs of the day without any further scares.