It was a fairly one-sided encounter, with the Tykes seizing the initiative early on through a penalty kick by Braam van Straaten in the sixth minute and never looked like relinquishing their grip on the contest.
Irish were forced into an on-field reorganisation after just three minutes when influential player/coach Brendan Venter was forced off with a serious knee injury.
Given that the former Springbok is due to head back to his native South Africa at the end of the season, it means that the Exiles are likely to be without their key inspiration – on the field at least – for one of the most crucial periods in their history.
Another former Springbok also left the field some minutes later – this time for Leeds – Van Straaten going off, No.10 Ross thus taking over the kicking duties.
Ross kicked two first half penalties, converted a try from Alan Dickens and then slotted a neat drop-goal to stretch the Tykes' lead to 19-3 at the break.
The Exiles battled on bravely, Mark Mapletoft kicking an early penalty and winger Paul Sackey showing tremendous pace to go over for a try.
But as the alarm bells started to ring for Leeds, second row Chris Murphy came to their rescue with a timely try that sealed the Exiles' fate.
For London Irish:Try: SackeyPens: Everitt, Mapletoft 2
For Leeds Tykes:Tries: Dickens, MurphyCon: Ross 2Pens: Ross 2, Van StraatenDG: Ross