THE CRICKET pitch conundrum deepened at Arundel yesterday as runs flowed, leaving Durham still with unexpected work to do on the fourth day to beat Sussex.

The tradition that pitches deteriorate as they wear is generally more marked at outgrounds, as when Durham were dismissed for 93 in their second innings here three years ago.

Yesterday they completed their recovery from 13 for four to amass 413, their highest score of the season, leaving Sussex to score 515 to win. They were 114 for two at the close.

The trend of flattening pitches had been emphasised by Somerset knocking off 400 to beat Nottinghamshire, and Sussex appeared neither intimidated nor disillusioned when they set about their task in mid-afternoon.

The pitch on which 12 wickets had fallen in the first 48 overs on the second day had metamorphosed into a bowlers' graveyard.

The transformation did not detract at all from the quality of Gordon Muchall's century as he began his innings when Steve Magoffin was looking unplayable after taking four for two in 15 balls.

But after resuming on 66 on an overcast morning, he and Paul Coughlin had little difficulty in extending their stand to 116.

In fact, in losing their four remaining wickets for the addition of 245 runs, Coughlin was the only one not to get out chasing quick runs.

He made an impressive 64 before edging Magoffin to second slip in the ninth over with the new ball. After his mesmerising opening burst Magoffin had to bowl a further 25 overs before bagging his fifth wicket.

Chris Rushworth holed out at deep square leg and John Hastings thrashed 91 before he swung across the line and was bowled when trying to hurry to his maiden century. He was two short of his best score for Victoria, but this was his highest for Durham.

Muchall spent 215 balls over his carefully-compiled century, which was rapturously received by the visiting fans, but immediately accelerated and was adjudged lbw for 115 when he tried to late cut leg-spinner Luke Wells.

As always when Muchall bats as well as this it is impossible to believe that his career average barely nudges 30.

At 32, it is 13 years since he made his debut but after a top score of 25 in 11 innings in 2012 he didn't feature in the championship the following year and has not been in the team at the start of the last two seasons.

When called up last year he made an imperious 158 not out at Trent Bridge without following up and Durham will hope his form lasts a little longer this time.

On Muchall's exit, Hastings maintained the acceleration with a straight six off Tim Linley when Sussex took the new ball.

But the fact that it caused few problems probably persuaded Durham that they needed 100 more and they were more circumspect when they emerged from lunch.

Hastings then got after the spinners, Wells and George Dockrell, pulling the left-armer for his fourth six immediately after reaching 50 off 47 balls.

Rushworth got off the mark by driving the same bowler for a straight six on his way to 19 before surrendering to Linley.

The on-loan Surrey seamer held Hastings in check by aiming at the blockhole and finally disturbed the timber with a slower ball to finish with eight wickets in the match.

The spinners took one between them in the second innings, adding to the mysteries of the pitch as Sussex had expected it to turn.

The sun had come out after lunch and those who wondered why Durham had batted on so long received their reply as Sussex's left-handed openers coasted to 51 in 11 overs at tea.

The only semblance of a breakthrough came when Rushworth was convinced he had Wells caught behind on 13.

The total had advanced to 60 when Mike Yardy drove loosely at Coughlin's fourth ball and edged to Michael Richardson.

Runs dried to a trickle thereafter and Ryan Pringle turned a couple past Wells' outside edge to provide some encouragement that the spinners might play a part today.

Pringle bowled 11 overs but Scott Borthwick didn't get on as Wells remained unbeaten on 53.

Matt Machan had made six when he edged Hastings just past Borthwick's left ear at second slip. But the big-hearted Australian kept running in and forced the Scotland left-hander to fence at one which he edged to Richardson.

Hopes of further inroads were stifled by home skipper Ed Joyce digging in to make five off 40 balls. Durham will want to see the back of him early this morning.