A day of surprises at Hove ended with Sussex fighting hard to build on last week's first Championship win of the season.

The first shock was that Chris Adams missed his first four-day game since the last match of the 2002 season, a run of 84 successive appearances, after he ricked his back in the pre-match warm-ups at Whitgift School on Wednesday.

It was even more of a surprise that Matt Prior, rather than Mike Yardy, led the side instead.

Yardy was appointed vice-captain last season and at the end of it, after leading Sussex to the title, Adams said he would be happy to play under his supposed successor one day.

He led the side six times in Adams' absence in 2007 while Prior's last taste of captaincy, a one-day game at Bristol more than a year ago, came in a match which Yardy missed because of injury.

Coach Mark Robinson cleared up the mystery. He said: "We haven't got an official vice-captain as such. Yards did it last year but he came to us in pre-season and said he wanted to concentrate on his own game without that added responsibility. Matt is obviously in a good place at the moment because of the form he was in and was the obvious choice for this match.

"Obviously if Chris was to be out for three months we would have to make a decision but at the moment we're looking at it on a game-by-game basis."

Prior did get his first job right by winning the toss but it was one of those damp, overcast mornings when he probably wished the coin had not landed in his favour.

His decision to bat first was starting to look like a misjudgement when Sussex limped to 79-5 after lunch as Steve Harmison threatened to run riot with some high-class fast bowling down the slope.

Then came another surprise as Sussex were pulled around by Chris Nash, who went into the game with just 29 runs in his previous five first-class innings, and Adams' replacement Rory Hamilton-Brown, who was making his Championship debut.

They added 84 in 25 overs for the sixth wicket with Nash lodging his highest Championship score of the season and Hamilton-Brown an attractive 62. Although Sussex's 214 was under-par, they fought back with the ball by taking three quick wickets before the close.

Nash could easily have put his feet up the day after Sussex's tense win over Nottinghamshire a week ago but he chose to try and rediscover his form in the Sussex League for Horsham and will have felt a whole lot better after scoring 101.

But there is a world of difference between facing Hastings' attack and a fired-up Harmison, who clearly has a point to prove after losing his England place.

Harmison maintained exemplary control to go with his hostile pace and only conceded his first runs off the bat when Luke Wright streakily top-edged over the slips in his 11th over. He had earlier yorked Carl Hopkinson and came round the wicket to uproot Yardy's off stump but shifting Nash proved a lot tougher.

Nash got a life on six when Phil Mustard dropped him behind the stumps but gradually the confidence began to return to his strokeplay.

Having lodged the 14th 50 of his career, Nash must have thought this was the day he would finally convert one into a hundred but he was bowled via an inside edge, having batted for four hours, faced 171 balls and hit seven fours.

Harmison was the successful bowler but it was Steve's younger brother Ben who did the damage. Harmison junior had only taken five first-class wickets at 71 but he finished with 4-43, including Prior with his first ball.

Hamilton-Brown wasn't the only Sussex batsman to have a torrid time against Harmison senior and he was dropped on nought at slip by Neil McKenzie.

As the sun came out and the ball got softer so batting became easier and the 20-year-old showcased some impressive shots on both sides of the wicket.

A last-wicket stand between Robin Martin-Jenkins and Corey Collymore of 24 in 14 overs earned Sussex an unexpected batting point and the value of those runs became more apparent when they took three wickets in 11 balls.

Collymore trapped Michael Di Venuto on his crease and sent nightwatchman Mark Davies's off stump carthweeling in his third over before Jason Lewry had Mark Stoneman well taken at first slip to leave the first day's honours just about even.