Matt Prior made the most of his promotion up the Sussex order by scoring his first Championship hundred since last August.

Prior illuminated a rain-affected first day at Arundel by making 103 against Nottinghamshire after opening the innings because Ian Ward had a virus.

His was one of three wickets to fall in as many overs after tea, but Chris Adams and Robin Martin-Jenkins batted with increasing fluency and Sussex will resume on 251-5 today.

Adams seemed determined not to waste the advantage of batting first on a typical Arundel pitch which is likely to give more help to the bowlers as the match progresses.

Prior has put them in a good position although he insists he is not after an opener's slot on a permanent basis.

He said: "It's not something for the long term because I want to carry on keeping wicket. I want to try and get up the order but the best spot is probably going to be four or five.

"But when I knew on Tuesday that Wardy was crook I told Chris that I'd be up for opening. I like a challenge and to keep pushing myself.

"The pitch is quite slow and one or two balls stopped in the pitch which made it hard for driving. I had a bit of luck but I enjoyed myself and hopefully we can kick on because I think it's the sort of pitch which our bowlers can get a bit out of."

Promoting Prior was the obvious move even though his experience of opening in first-class cricket has been limited to just one game at the start of the season, when he made 70 for the MCC against champions Warwickshire.

He has opened in limited overs since the start of last season with increasing success and the fundamentals of the job, whether it is one-day or four-day cricket, are just the same to him.

There was never any danger that the 23-year-old would rein in his natural instincts which is to try and dominate the bowlers from the start. And inevitably, amidst a flurry of powerful drives through his favourite off side areas which brought him the majority of his 18 boundaries, there were one or two loose shots as well.

He was badly missed by Chris Read on 55, when he edged a delivery from Mark Ealham which the wicketkeeper dropped as he dived in front of slip, and AJ Harris, who produced the occasional jaffa amidst a lot of mediocrity, came close to finding the edge on a couple of occasions when he tempted him into ambitious drives outside off stump.

But spectators denied any action until 2.30pm because of rain will prefer to remember crunching front-foot shots and an arrow-straight drive off Harris which took him to his 50 for the third time this season.

While Prior made hay, Richard Montgomerie could only watch and wonder what might have been. After making 184 in his last Championship innings a fortnight ago, he was run out for a duck off the seventh ball of the match.

Prior sent him back after he called for a leg bye and Montgomerie slipped as he turned and was beaten by Russell Warren's throw from behind square to the bowler's end.

Mike Yardy looked untroubled as he helped Prior add 98 in 24 overs before Harris found just enough lateral movement to find the edge.

Murray Goodwin was even more annoyed with himself. The Zimbabwean had moved effortlessly on to 39 when he was caught at slip as he tried to run Graeme Swann's off spin down to third man after adding 85 in just 15 overs with Prior.

Prior went hard at Greg Smith in the 43rd over and got the feintest of nicks and Tim Ambrose's first Championship innings since the season's opener against Surrey lasted just two balls as Smith trapped him in front.

Sussex had lost three wickets for ten runs but Adams and Martin-Jenkins added 56 with increasing fluency.

The county's prospects of a much-needed second Championship win of the season will improve if Ryan Sidebottom, is unable to bowl again.

Sidebottom pulled up with a side strain in his fifth over.

Neil Turk continued his excellent run of form by hitting an unbeaten 96 but, that apart, it was a disappointing opening day for Sussex 2nd XI againsts Hampshire at Hove.

Sussex were dismissed for 192 after winning the toss in the Championship match, and Hampshire then reached 89 without loss. Turk fired 11 fours from 171 balls and shared a third-wicket stand off 69 with Sean Heather (26).