Murray Goodwin fell for 99 in the final over of the day but leaders Sussex closed in a strong position at 420-5.

Eight points ahead of Lancashire, Sussex chose to bat on an overcast morning and lost Carl Hopkinson to a direct hit in the third over.

But England all-rounder Michael Yardy overcame a difficult start to hit a defiant third century of the campaign, his team striking 64 fours and a six.

Three successive century stands ensured maximum batting points for Sussex.

After Hopkinson needlessly fell for a duck to Samit Patel's throw from short cover, Yardy and Richard Montgomerie began the recovery.

Both could also have been run-out, Montgomerie diving to beat Darren Bicknell's throw when pushing for a third and Yardy, having resigned himself to dismissal in mid-pitch, saw Will Smith's shy at the stumps narrowly miss.

Montgomerie was particularly prolific through the mid-wicket area and hit 10 fours to reach fifty off 79 balls, his 73rd first-class half-century.

Yardy, who sliced between the two gully fielders when on one, had another reprieve on 38 when he edged AJ Harris to first slip and Stephen Fleming spilled the straightforward chance above his head.

The New Zealand captain left the field with blood dripping from his finger and was taken to hospital, returning later with four stitches but no fracture.

Montgomerie brought up the 100 partnership with a trademark whip off his toes for four more, but snicked a drive 18 short of a century.

As batting conditions eased in the afternoon sunshine, Goodwin punished some loose bowling to add 110 with Yardy, who finally fell lbw for 119 to a quicker one from left-arm spinner Patel.

Goodwin, Sussex's leading run-scorer, coasted to his seventh fifty of the campaign from 75 balls, despite being slightly hampered by a hand injury.

Skipper Chris Adams maintained the pace, flicking Harris through the leg-side for six and adding consecutive fours, but having reached 72 he pulled straight to substitute fielder Gareth Clough at mid-wicket.

In glorious evening Nottingham sunshine, Matt Prior hit four fours in an over from Ryan Sidebottom before losing Goodwin, who got an inside edge into his stumps looking for his seventh Championship century.

Yardy was pleased with his side's performance on the opening day.

"We need to finish well and we set up a good platform," he said. "If someone had offered us that before the start we'd have been over the moon.

"The pitch is quite dry, I took a long time to find my rhythm but once I got in I felt really good, I tried to play more expansively and it worked."