It took Robinson all of two minutes to make the first of Sale's four first-half tries before leading the Irish a merry dance in making further tries for Steve Hanley and Steve Davidson. Robinson himself accounted for the fifth in a 43-18 home win.
Having jumped above Irish into eighth place, Sale must beat Wasps at Hey-wood Road on Saturday to be sure of finishing there, irrespective of the outcome of the Exiles' final match, at home to Gloucester next Monday.
A try in the seventh minute of injury-time from 35-year- old Scottish prop George Graham gave Newcastle an astonishing 39-36 win at Rotherham.
The Yorkshire club, long doomed to relegation after one season in the Premier-ship, had promised to reward their shrinking crowd with only their third win of the season.
They led 36-13 only to concede four tries in the last 20 minutes. Gary Armstrong, place-kicking for the first time this season with both Jonny Wilkinson and Dave Walder taking a breather, responded with six goals.