Notts' home side edges the opening day as Proteas seamer notches his seventh five-wicket haul.
Dean Elgar and Jordan Cox made impressive debuts for Essex, but it was Dane Paterson, also from South Africa, who stole the show on the opening day of the Vitality County Championship season at Trent Bridge.
Elgar, who retired from international cricket earlier this year, proved capable of filling the void left by Sir Alastair Cook, defying typical opening-day conditions with a stylish 80.
He formed a 112-run partnership for the third wicket with the talented former Kent batter Cox, who scored 84. However, Paterson, who returned from his winter break on Wednesday, led a Nottinghamshire fightback by taking 5 wickets for 49 runs with his clever medium pace.
Paterson bowled Elgar with one of several outstanding deliveries as Essex, who were runners-up in Division One last season, slipped from 170 for 2 to 176 for 5. They eventually closed on 244 for 9 from 77 overs, with time having been lost due to a wet outfield at the start and bad light in the evening.
Cox impressed his new employers with a mature performance, but he lacked any meaningful support apart from Elgar.
Elgar introduced himself with a boundary off the first ball, hitting a Brett Hutton half-volley through cover. Despite testing conditions, the South African managed to score 31 runs from 62 balls before lunch, surviving several tricky moments without giving any chances.
Feroze Kushi, who had not played a Championship match since last June but was preferred over Nick Browne to open with Elgar, scored a quick 18 runs, including an audacious six off Nottinghamshire debutant Dillon Pennington. Pennington then managed to square him up and make him edge to first slip.
Paterson, who has been Nottinghamshire's most consistent performer with the ball, replaced Pennington at the pavilion end. He quickly enticed Tom Westley into playing a shot outside off stump, and wicketkeeper Joe Clarke made a good diving catch to his right.
Clarke is keeping wicket in this match because Nottinghamshire's batting line-up, which has been strengthened by the return of England's Ben Duckett for his first Championship match in 11 months and the addition of Jack Haynes, another signing from Worcestershire, could not include regular keeper Tom Moores.
As Nottinghamshire searched for a breakthrough with the Kookaburra ball, Elgar and Cox dominated the afternoon session. Elgar completed his half-century off 86 balls, while Cox reached the same milestone in 76 balls after hitting leg-spinner Calvin Harrison for a six over the straight boundary.
Elgar played with great confidence, drawing on his experience from previous county stints with Somerset and Surrey. He appeared to be on track for a debut century, but unfortunately, Paterson took wickets in consecutive overs before tea, ending the session.
Paterson, who is back for his fourth season at Trent Bridge after taking over 50 wickets in each of the previous three seasons, bowled his compatriot with the ball of the day. The delivery was angled in from round the wicket and straightened just enough to pass the edge and clip the off bail.
Moments later, Paterson celebrated again as another delivery trapped new batter Matt Critchley, leaving Essex at 174 for 4 at tea. The score quickly became 176 for 5 on the resumption as Paterson continued his excellent spell by dismissing Paul Walter, who was caught behind, to claim a third wicket in the space of 16 balls.
The bowler took his fifth wicket soon after, with Adam Rossington being deceived by another superb ball that removed his off stump. This gave the bowler figures of four for 24 from an eight-over second spell, and marked his seventh five-wicket haul in Championship cricket.
Although Cox had hopes of scoring a debut hundred and had overtaken Elgar with his 11th four, his aspirations were thwarted when Harrison turned one past his defensive bat to bowl him on the very next ball. Lyndon James dismissed Simon Harmer and Shane Snater, earning Nottinghamshire three bowling points. Essex is still searching for their first batting point.