The predatory instincts of Swedish striker Henrik Larsson made it advantage Celtic in thein the so-called Battle of Britain at Celtic Park.
Larsson struck with just five minutes left of a pulsating 90 minutes to settle the first legand set up a finely balanced second leg at Ewood Park.
David Thompson headed a John Hartson header off the line only for Larsson to stab homethe rebound from close range.
Blackburn dominated in terms of possession but just could not unlock a resilient homedefence in which Joos Valgaeren was outstanding.
Rab Douglas also made some important saves at key moments to ensure Blackburn did notnab an away goal.
Celtic almost snatched the opener after nine minutes when it took an instinctive one-handed save from Brad Friedel to keep out a header from Stilian Petrov after excellentwork by Didier Agathe.
But Blackburn then took a grip and frustrated Celtic by keeping the ball for long spells inthe first half.
A Martin Taylor shot was blocked by Ulrik Laursen and, eight minutes from half time, BoboBalde made a fine block to deny Dwight Yorke after a great run from David Thompson.
Four minutes later, David Thompson picked out Yorke again with a clever piece of skill butthis time Laursen managed to make the block.
Andy Cole replaced Egil Ostenstad at half time to give Celtic a new threat but the homedefence stood firm.
Chris Sutton had an opportunity for Celtic five minutes into the second half after amisplaced header from Garry Flitcroft but Friedel saved comfortably at his left-hand post.
Cole saw a shot blocked by Balde at the other end and Douglas had to react quickly tosnatch the ball away from Damien Duff.
Douglas was again called into action with ten minutes left to turn a long-range effort fromDavid Dunn past his post.
With the match heading for stalemate, Larsson struck with a typical poacher's goal afterBlackburn failed to pick up Hartson at an Alan Thompson corner