A record partnership saw Sussex take control after a dominant first session from the Northamptonshire bowlers on Day 1.
Adam Rossington and Ben Curran came into the side in place of Josh Cobb and the injured Rob Newton, with captain Alex Wakely winning the toss and choosing to bowl. The Sussex openers safely negotiated the first few overs of the day before Sanderson struck three times in as many overs to reduce the visitors to 27 for 3.
Salt was the first to go, Sanderson finding some movement to beat the inside edge and uproot off stump. Haines was undone by the same movement, looking to push through the legside but his leading edge lobbed gently to Bavuma at point. van Zyl was the last of the trio, looking to drive on the up but finding Keogh at mid off. Buck came into the attack with immediate effect, a misjudged leave to a ball jagging back saw middle stump smashed in half to see Sussex 35 for 4.
Procter and Overton took wickets in successive overs to have Sussex on the ropes at 68 for 6. Procter finding the outside edge through to a diving Rossington, with Overton sending down an unplayable outswinging Yorker to send off stump flying for a second time. A stroke of good fortune for Chris Jordan would prove costly for Northamptonshire, an outside edge from his first delivery splitting between keeper and slip and away to the boundary for four.
Jordan and Sussex captain Brown kept Northamptonshire wicketless in the afternoon session. The pair regularly finding the boundary to bring up the 150 partnership and lift Sussex from a dangerous position to a far more comfortable 228/6 at tea. Both batsmen reached centuries shortly after tea before bringing up the 200 run partnership and didn’t stop there. The score passed 350 before the close, both batsmen still unbeaten at the end of play. After an unlikely start, Sussex now in the commanding position of 370/6.
Sussex 370/6 (Sanderson 3/71, Overton 1/69)