Harry Gurney took a hat-trick to give Nottinghamshire the early impetus against Sussex on day three of their LV= County Championship Division One clash at the BrightonandHoveJobs.com County Ground.
Ed Cowan and James Taylor then put on a third-wicket stand worth 151 in 45 overs before a three-wicket burst by Chris Jordan brought Sussex back into the match.
Nottinghamshire, with one wicket remaining on 304 for nine in their second innings, lead by 354 and both sides will go into the final day with a realistic chance of winning the game.
Sussex resumed in the morning on 290 for six, with hopes of getting level with Nottinghamshire's first-innings total, but they were bundled out within four overs.
Jordan had added just a single to his overnight 21 when he was run out off the fourth delivery of the morning. He was sent back by Ben Brown and failed to beat the throw from Taylor.
Three overs later, Gurney, achieving both swing and bounce from the Cromwell Road End, took the first-hat-trick of his career.
First, Brown edged to Samit Patel at first slip, then James Anyon guided the ball to Steven Mullaney at third slip before Monty Panesar, playing an identical shot, was caught by Patel once more to give Gurney figures of 4-69 and Nottinghamshire's first hat-trick since 2006.
That gave the visitors an unexpected first-innings lead of 50.
Sussex seamer Stephen Magoffin took a wicket with his first ball to dismiss Notts opener Alex Hales, who clipped flat-footedly to midwicket, meaning four wickets had fallen in as many deliveries from the Cromwell Road End.
Sussex were right back in it when Magoffin struck again in his sixth over. Michael Lumb edged to the wicketkeeper and Nottinghamshire were 24 for two.
Cowan and Taylor then got on top of the Sussex attack. Panesar, in particular, struggled for length and rhythm in the afternoon session.
Cowan, a member of Australia's Ashes squad, reached his fifty when he top-edged a hook to fine-leg for six but then he chopped on a delivery from off-spinner Chris Nash for 81.
Taylor, for the second time this season, was out for 97 when he was caught down the leg side by Brown off Jordan.
The aggressive Jordan, like Gurney and Magoffin before him, enjoyed the extra bounce bowling down the hill from the Cromwell Road End. At 218 he surprised Patel with his bounce, and the batsman was caught behind.
Two overs later Mullaney could only fend off a rising delivery to square-leg. Panesar, bowling better at the end of the day, had Chris Read lbw before Magoffin bowled Ajmal Shahzad and had Luke Fletcher caught at slip first ball.
That brought Gurney to the wicket, but it was Paul Franks who saved the hat-trick when he clipped Magoffin for four to carry his bat with 56 overnight.