Irish Cup holders Glenavon crashed out 2-0 to Harland and Wolff Welders in their sixth round tie at Tillysburn.
David Rainey scored the opener with a fine 11th-minute header and Scott Davidson added the second after 74 to complete a deserved victory.
Portadown fared better, defeating Championship Two side Portstewart in Saturday's other early kick-off.
Gary Twigg netted his 14th goal of the season on 77 minutes, with Darren Murray firing in the second after 89.
Championship One outfit H&W Welders, managed by former Glenavon defender Gary Smyth, took an early lead when Rainey headed back across goal into the bottom corner after Mark Magnennis crossed to the back post.
James McGrath made a good diving save to deny Rainey, who was part of the Lurgan Blues' cup-winning squad last season, a second goal before the interval.
Declan O'Brien went close and hit the woodwork from a Kevin Braniff corner for Glenavon, who had survived a scare against Moyola Park in the previous round of the competition.
After the break, Michael McLellan shot just wide of the post and Magennis lobbed the goalkeeper but was just off-target.
Davidson struck to extend his side's lead with a simple finish after Magennis rolled the ball to him, and Rainey missed a good opportunity late on.
The Welders will have an opportunity to avenge their fifth-round exit at the hands of Ballymena United in the fifth round last year when the teams meet in the quarter-finals.
At Seahaven, three-times winners Portadown left it late to secure their passage into the last eight.
Johnny Stewart was unable to connect with a James Peden free-kick in the second minute, then at the other end, Murray was denied by Joel Madison and Tim Mouncey squandered two good chances.
Ex-Donegal Celtic forward Murray fired wide on two occasions, before Twigg rifled in off the post after his first attempt was blocked.
Murray followed up to score the second, pouncing after Mouncey's effort was saved by Madison, and then spilled.
H&W Welders manager Gary Smyth: "We were superb from start to finish - it was 1-0 at half-time but it could have been two or three, and it was a case of defending that lead in the second half.
"I thought we were pretty comfortable after the break and we could have had another couple in the end. We won't fear anyone in the next round if we are handed a home draw."
Irish Cup sixth round results
Carrick Rangers 3-1 Institute (after extra-time)
Ballyclare Comrades 0-0 Dungannon Swifts (Swifts won 5-4 on penalties)
Bangor 0-2 Crusaders
Cliftonville 1-2 Ballymena Utd
Linfield 5-0 Warrenpoint Town
Glentoran 4-1 Armagh City
H&W Welders 2-0 Glenavon
Portstewart 0-2 Portadown