Steve Smith was kept waiting for his first County Championship innings but had an excellent vantage point as Sussex team-mate Ollie Robinson ripped through Worcestershire.

The pair will be on opposing sides in this summer’s Ashes but are sharing a dressing room for now after Sussex somewhat controversially snapped up the former Australia captain for three Division Two matches.

He has been restricted to a fielding brief so far at New Road, watching from the slips and maybe making some mental notes as Robinson took top billing with seven wickets for 59 runs in Worcestershire’s 264 all out.

Robinson was nursing soreness in his back towards the end of England’s winter and this was just his second match of the season, but the seamer was a cut above as he took the first four wickets to fall.

Worcestershire recovered from 44 for five, with Adam Hose’s 59 followed by belligerent half-centuries down the order from Matthew Waite and Joe Leach, who put on 103 in 14.4 overs when Robinson was out of the attack.

But Robinson found the top of Waite’s off-stump for 59 from 54 deliveries in his first over back and then combined with Smith to remove Waite for a run-a-ball 53 as Worcestershire folded before Sussex closed on 63 for one at the end of the opening day, shortened by 21 overs because of bad light.

The expectation might have been on Sussex to bat first upon winning the toss under gloriously sunny skies but Cheteshwar Pujara’s decision to field was vindicated by Robinson’s opening burst of 7-0-30-4.

Ed Pollock collected an all-run four from the first ball of the day but another injudicious drive later in the over caught the outside edge and flew to Tom Clark, who moved across Smith to take the catch.

Azhar Ali, the ex-Pakistan skipper and jewel in Worcestershire’s crown, was caught on the crease and adjudged lbw by one angling into him while Jack Haynes, who bagged a pair against Gloucestershire last week, made just a single here before being squared up and nicking low to Tom Alsop at first slip.

Robinson had his and Sussex’s fourth when he snaked through a gap between Jake Libby’s bat and pad to uproot middle stump while Worcestershire were five down inside 50 minutes when captain Brett D’Oliveira was surprised by the extra bounce from Fynn Hudson-Prentice and an edge squirted to third slip.

Hose and Gareth Roderick settled once Robinson was withdrawn from the firing line, the pair putting on 92 either side of lunch, showing the kind of resistance that eluded those higher up the order.

Sean Hunt got a deserved wicket when Roderick feathered through to Oli Carter for 39 and the end looked nigh when Hose’s stumps were rearranged by Henry Crocombe’s precise yorker.

But Waite gave an indication of what was to come when he twice freed his arms off Hunt for leg-side sixes – another followed off Crocombe – while Leach found the boundary rope with regularity in a counter-attacking union that led to Pujara returning to Robinson sooner than may have been anticipated.

Robinson needed just six balls to break the enterprising stand, locating the top of off-stump to dismiss Waite, before Smith had his first tangible moment of the match when Leach was drawn into a stroke off the rampant bowler.

Last man Ben Gibbon lasted just two balls as he was pinned lbw to become Robinson’s seventh victim, with Worcestershire losing their final three wickets inside 13 deliveries.

Sussex openers Ali Orr and Clark showed better judgement than their Worcestershire counterparts, putting on 37 in gloomy conditions.

Clark was punished for driving loosely off Josh Tongue to depart for 12 but Orr was there on 37 not out, with Alsop unbeaten on 11, when the players came off under darkening skies.