Hampshire bowler Tino Best blazed in at full speed to take two early wickets but all three results are still possible at the Ageas Bowl.
Will Smith declared on 223 for nine – with just Ryan McLaren departing for a well-made 43 in the morning, lbw to Harry Gurney – to give the left armer a five-wicket haul.
Nottinghamshire, having been set 305 to win in a minimum of 86 overs, toiled against Best’s pace – but kept the run rate moving.
After hitting Steven Mullaney on the back with a fierce bouncer, Best pitched up to Jake Libby to find a nick through to Adam Wheater.
Before Michael Lumb was adjudged leg before to the West Indian after a long deliberation by umpire Nick Cook.
Mullaney departed to the final ball before lunch when McLaren got one to bounce before catching the edge to first slip - Notts still needing 255.