With only ten minutes to go, it was still scoreless and DC were aiming for a replay but Joe Gormley broke their hearts on 80 minutes and then right on the final whistle George McMullen made the final score 2-0.
Basement Championship One side Bangor gave Glentoran a huge fright as they raced into a two goal lead with Lambe and Doran putting the home side after 11 minutes.
However, the Glens bounced back to win 5-2 thanks to goals from Andy Waterworth, Jamie Callacher, Colin Nixon, Marcus Kane and David Howland.
A hat-trick in 11 minutes from Paul Heatley was the highlight of a blistering first half at Seaview as Crusaders romped into the quarter-finals.
Indeed, all of the goals came in an eventful first 45 minutes as the Crues ran out 4-1 winners.
Glenavon were hit with an early blow on four minutes when a free kick by Gareth McKeown was met by Timmy Adamson, his header appeared to cross the line despite the efforts of goalkeeper Andy Coleman.
It was soon 2-0 when a great break by David Rainey saw him deliver a great cross and Paul Heatley directed a firm header into the net.
Glenavon tried to respond and Mark Farren was almost in, however, Lacroix was quick off his line to smother the ball.
The tie was all but over on 21 minutes with another excellent finish giving the Crues a 3-0 lead, this time Heatley drilling in from 18 yards out.
Heatley struck again a few minutes later to bag his hat-trick as the Glenavon defence was ripped apart again with McMaster on the break, his cross left Heatley with a simple tap-in.
Glenavon's Matthew Rooney did pull a goal back for the visitors right at the end of what was a dismal first half.
Heatley almost grabbed his fourth after the restart but his shot fizzed wide of the post. At the other end Glenavon sub Ciaran Doherty was not too far away with a low drive.
Coleraine snatched a late winner at Ballymena just when it looked as if they would have to do it all again.
David Scullion was the hero for the visitors with a 90th winner strike. Earlier, Alan Taggart had given Ballymena the lead but that was cancelled out by Curtis Allen.
A Shaun Maher own goal put Coleraine ahead again before Gary Liggett made it 2-2 on 88 minutes.
Tempers flared in the game between Institute and Kilmore Rec with three red cards brandished.
Taylor and Curran for Institute and Cheevers for the visitors who went through 2-0 with goals from Andy Telford and a Stephen Douglas penalty.
Knockbreda came out on top at Lurgan Celtic, who had two players sent off. The Championship Two league leaders proved too strong winning 3-0 thanks to goals from Miguel Chines, Young and Wright.
At Shamrock Park, it took a late goal from Chris Casement to see Portadown to a 1-0 win over a battling Ards side.
The tie between Lisburn Distillery and Dundela was postponed because of a water-logged pitch.
One Premiership League game was played with Linfield winning 4-1 at Dungannon Swifts.
On target for the Blues were Brian McCaul, Gary Browne, Philip Lowry and Mark McAllister. Ryan Harper had put the Swifts ahead.
Meanwhile, the Irish Cup quarter-finals draw took place on Saturday evening. The matches are as follows:
Knockbreda v Glentoran
Cliftonville v Kilmore Rec
Coleraine v Portadown
Crusaders v Lisburn Distillery or Dundela
The clashes will be played on Saturday, 2 March.
Irish Cup sixth round results from Saturday 9 February 2013
Coleraine 3 - 2 Ballymena
Glentoran 5 - 2 Bangor
Cliftonville 2 - 0 Donegal Celtic
Portadown 1 - 0 Ards
Crusaders 4 - 1 Glenavon
Knockabreda 3 - 0 Lurgan Celtic
Kilmore Rec 2 - Institute 0
Danske Bank Premiership results from Saturday 9 February 2013
Linfield 4-1 Dungannon Swifts