Leinster were made to fight all the way over a never-say-die Glasgow team in Friday's Celtic Cup quarter-final at Lansdowne Road.
CELTIC CUP QUARTER-FINAL
Leinster (21) 33
Tries: Dempsey, Costello, D'Arcy 2, O'Driscoll
Cons: Holwell 4
Glasgow (9) 24
Tries: Dearlove, S Lamont
Pens: Parks 4
The Scots had trailed 21-3 after early Leinster tries from Girvan Dempsey, Victor Costello and Gordon D'Arcy.
But they fought back to lead thanks to the kicking of Dan Parks and tries from Paul Dearlove and Sean Lamont.
Leinster recovered to book their place in the semis-finals, Brian O'Driscoll and D'Arcy getting further touchdowns.
The first of the game's seven tries came when Irish international Dempsey crossed in the left after an O'Driscoll and D'Arcy build-up.
David Holwell converted but a Parks penalty trimmed the lead to 7-3.
Number eight Victor Costello, in his 126th match for the Irish province, scored out on the same flank, with Holwell adding the extra two points.
On 34 minutes, D'Arcy broke through for Leinster's third try, which Holwell again converted.
Two penalties late in the first half brought the score back to 21-9 - and the gap closed further just two minutes after the restart as number eight Dearlove touched down.
Ten minutes later, Malcolm O'Kelly was penalised for a second movement when trying to score under the posts and Glasgow broke the length of the pitch to score a try through Lamont.
The conversion by Parks tied the score at 21-21 and Glasgow went ahead for the first time through another Parks penalty.
Leinster looked in trouble but they regained the upper hand with Irish skipper O'Driscoll going in at the left corner and man-of-the-match D'Arcy getting his second try.
Leinster: Dempsey, Brown, O'Driscoll, D'Arcy, Lewis, Holwell, Easterby, Corrigan, S. Byrne, Nebbett, Gissing, Cullen, Dillon, Gleeson, Costello.
Replacements: E. Byrne, D. Blaney, O'Kelly, Jennings, O'Riordan, Horgan, D. Hickie.
Glasgow: Howarth, R. Lamont, Henderson, Barrow, S. Lamont, Parks, Beveridge, Tckachuk, Lawson, Murray, Beardshaw, Turner, Swindall, Petrie, Dearlove.
Replacements: Thomson, Prescott, Hall, Wilson, Pinder, Logan, Craig.
Referee: N Williams (Wales)