Live coverage of the second leg of this Uefa Cup semi-final from the Estadio do Bessa in Porto, Portugal (kickoff 8.00pm). The tie is delicately poised after a 1-1 draw at Celtic Park a fortnight ago - Boavista grabbed a precious away goal when Celtic's Joos Valgaeren put through his own net, but Henrik Larsson quickly equalised, only to then miss a penalty.
Martin O'Neill's men must keep things tight, and much depends on gargantuan central defenders Johan Mjallby and Bobo Balde, but their side is also built for goals with the prolific Larsson and the powerful John Hartson. The Bhoys can win away, as proved by their 2-0 quarter-final triumph at Liverpool, and they've also beaten Blackburn, Celta Vigo and VfB Stuttgart on their way to what they hope will be their first European final since 1970, in Seville on 21 May.
Presented by Gary Lineker, with analysts Alan Hansen, Mark Lawrenson and Kenny Dalglish. Commentary can also be heard on Radio Five Live.
(Highlights of the match can be seen at 11.30pm on BBC3)