After going nearly four years without tasting Championship defeat at Hove, Sussex will have to work hard over the next two days to avoid a second successive home loss.

And it was no surprise that the man responsible for putting Lancashire in a position of strength was their captain Stuart Law.

The Queenslander will turn 40 in October but age does not appear to be diminishing his physical or mental powers as he batted through a hot day to lodge his 100th hundred in all competitions, 79th in first-class cricket and seventh against Sussex.

It is hard to recall Law making a mistake until he reached 128 and top-edged a sweep which Chris Adams, running round from slip, could not cling on to as he dived forward with an outstretched hand.

Law resumes tomorrow unbeaten on 156, made from 277 balls with 17 fours, the last two struck off Jason Lewry to take him past 150 for the 27th time in his career. With two wickets in hand, Lancashire lead by 129.

The extra responsibility of captaincy is the only explanation why such a consistent performer as Law had not scored a Championship hundred since taking over at the start of the season. In fact, he had only passed fifty once but there was an inevitability that he would get a big un once he had played himself in.

To that end he was helped considerably by a ragged bowling performance from Sussex in the first 40 minutes when they leaked 51 runs, including three sets of four byes in the same over from Corey Collymore.

There was nothing like the same swing movement the Sussex had enjoyed on the first day while Mushtaq Ahmed - by his own admission only 70 per cent fit - was clearly some way short of his best.

If trying to remove Law proved as troublesome as the swarm of bees which forced several fielders to take cover for a couple of minutes in mid-afternoon, what Sussex could not have bargained for was the obdurate support he received from nightwatchman Gary Keedy.

The left-hander made a career-best 67 - only his second first-class fifty in 183 innings - in three hours, showing the application missing from much of Sussex's first-innings batting. He helped Law add 160 in 48 overs and was even outscoring his partner at one stage.

Although Mushtaq finally had Keedy caught at silly point it was Ollie Rayner who looked Sussex's more potent spin threat.

The off-spinner's introduction in the 68th over drew ironic cheers from supporters who felt he should have been bowling earlier and when he beat Steven Croft's defensive push in his fourth over they probably felt they had a point.

With Mark Ramprakash and Justin Langer already among his victims this season, Rayner is developing a reputation as a bowler who gets good players out and while Law's wicket would have been more coveted yesterday the 22-year-old would have been thrilled nonetheless to have snared Andrew Flintoff.

Big Fred at least avoided a fourth successive Championship duck when he plonked his second ball over mid on for four but in 12 minutes at the crease he looked short of confidence and when he tried to hit his way back into form only succeeded in mis-cueing to mid-wicket where sub fielder Will Adkin enjoyed the biggest moment of his career so far.

Mushtaq came back after tea to trap Luke Sutton with his googly but not until he had added 89 in 28 overs with the remorseless Law.

Meanwhile, Sussex gained swift revenge for their surprise defeat at the hands of MCC Young Cricketers in the Second XI Trophy by beating the same opposition by six wickets at Horsham.

Sussex dismissed the Young Cricketers for 152 in 39.4 overs and then reached their target with 14.3 overs in hand.

Matt Machen helped Sussex to victory by firing 56 with seven fours from 48 balls.

Off-spinner Rory Hamilton-Brown earlier took 3-6 in three overs to peg the visitors back while Ragheb Aga bagged 3-21.