Middlesex 269 (Robinson 4-46) and 209 (Magoffin 4-49, Robinson 4-62) beat Sussex 192 and 207 (Yardy 52, Dexter 4-41, Finn 4-51) by 79 runs
Scorecard
Middlesex, unfancied as Championship contenders after their poor finish to last season, cemented top spot in the First Division by beating Sussex by 79 runs at Hove to claim their third successive win.
Chasing 287 to win, Sussex were 92 for 1 but lost wickets regularly thereafter once Neil Dexter had removed Matt Machan and skipper Ed Joyce in the space of seven deliveries.
Dexter finished with 4 for 41 including opener Mike Yardy, who was dismissed off the last ball before tea for 52, the only half-century of the match.
Making the highest total of the contest was always going to be difficult for Sussex. A dry, cracked pitch made batting a lottery at times as the ball often bounced erratically, but Sussex conceded 84 extras in the match and the Middlesex attacked showed more discipline.
Adam Voges, Middlesex captain, who now teams up with Australia, said: "My honest assessment is that it wasn't a great wicket. I just felt the variable bounce combined with the sideways movement from the first day made it difficult and the fact that only one batsman got to 50 proved that.
"The sun came out today and it played a bit better and the 83 runs our last four wickets put on were like gold. Our tail did a great job in both innings and gave us a great bit of momentum.
"We have started tremendously well. It's a close knit group and they are very talented so there's no reason why we can't continue our good start. Steve Finn has bowled well all season and has just been a bit unlucky at times so it was good to see him get four wickets. His pace is up and his areas are good.
"I had a bit of a hunch with Neil Dexter and he did a terrific job. He found enough sideways movement and getting Michael Yardy just before tea was crucial. He gets wickets in clusters."
Yardy had put on 56 with Chris Nash for the first wicket then Machan (29) counter-attacked impressively to put Sussex in a decent position before Dexter struck.
With his second ball he had Machan held at mid-on off a miscued drive before Joyce fell for a duck, caught behind off a thin edge as pushed forward uncertainly.
Yardy held the innings together but lacked support at the other end. Steve Finn, who finished with 4 for 51, bowled Craig Cachopa with a break-back and after tea he halted a dangerous stand of 38 for the eighth wicket between Ben Brown (29) and Ollie Robinson when Brown was caught in the covers off a top-edged pull.
Dexter bowled Luke Wright (12) with a nip-backer and it was left to Finn to finish things off with two of the last three wickets to fall.
Earlier, Middlesex had added 83 runs for their last four wickets before being dismissed for 209 in their second innings.
Yardy took his sixth catch of the match at second slip to remove Rayner and give Robinson his fourth wicket before John Simpson (34) and James Harris (28) added 55 for the eighth wicket with some bold strokeplay.
Steve Magoffin ended the stand when he knocked back Simpson's middle stump and Harris fell in the next over, feathering an edge off Matt Hobden.
Magoffin completed match figures of 7 for 110 from 43.4 overs, when Finn was caught in the covers off a top edge, while Robinson took eight wickets on his home debut, although they were only crumbs of comfort for a Sussex attack without Shahzad in the second innings because of his arm injury.
