Angus Robson recorded a maiden first-class century but bottom-placed Leicestershire failed to make the best of his 115 on day one of their LV= County Championship Division Two tussle with promotion-chasing Hampshire.
After captain Josh Cobb decided to bat first at the Ageas Bowl, Leicestershire reached 301 for nine from 97 overs at the close, a respectable score but one which could have been more substantial.
From 249 for four, built around important stands that 22-year-old Robson shared for the third and fourth wickets with Cobb and Niall O'Brien, Leicestershire lost five wickets in the last session.
The collapse looked to hand the initiative back to the second-placed home side who are bidding for their sixth championship win of the season.
Cobb must have wondered if he had made the right choice as Greg Smith departed in the sixth over and Ned Eckersley in the 10th, both to Matt Coles.
And when Dan Redfern was taken smartly in the slips by Sean Ervine off Chris Wood, Leicestershire were on a precarious 58 for three.
But then Cobb joined Robson, and in 44 overs Leicestershire's fourth-wicket pair put together the best partnership of the innings, worth 116 precious runs as Hampshire failed to exploit their first-session superiority.
Cobb hit eight fours in his 52 before left-arm spinner Danny Briggs found a way through his defences with the team score on 174.
There was little respite for Hampshire though as O'Brien joined Robson in another important stand, this time adding 75 for the fifth wicket.
— Matt Howell (@mjhowler) August 31, 2014
Spinner Liam Dawson precipitated the late Leicestershire slump when O'Brien edged him to Ervine at slip for 44, and from a position of authority the visiting team fell away after tea, at one point losing five wickets for 28 in 13 overs.
Rob Taylor was stumped by Adam Wheater in Dawson's next over, before Robson's vigil, spread over five hours and 17 minutes, came to an end when James Tomlinson at last found the edge.
Robson, whose previous best score was 92, hit 17 fours and faced 265 balls but the shame from Leicestershire's viewpoint was that his team were unable to sustain the progress he had made over the 88 overs he had spent at the crease.
Jigar Naik became Coles' third victim, pinned leg before, and Tomlinson accepted a return catch from Alex Wyatt to leave Leicestershire on 277 for nine.
It was a situation improved only by an unbeaten last-wicket stand of 24 between Charlie Shreck and Atif Sheikh, making his Leicestershire first-class debut.
Coles finished as the most successful bowler in terms of wickets, although his 3-106 came off only 19 overs, while spinners Dawson and Briggs took three of the wickets, Briggs a picture of accuracy in conceding only 19 runs from 16 overs.
Robson - brother of England batsman Sam - said of his landmark innings: "It was a great day for me. I am thrilled to get my first century.
"Hampshire bowled well all day and they made us work for our runs. We had to rein in ourselves in terms of shot selection. There were periods when I was stuck for runs so patience was the key.
"When I got into the nineties I tried to relax. It was good to have Niall out there keeping me calm."
Hampshire captain Jimmy Adams said: "It was a shared day. If we can knock over the last pair early tomorrow we would have the edge.
"Five wickets after tea was perfect for us and took away the advantage they had at 249 for four. If we had taken one or two chances we might have limited them to 250."