Two goals by Andy McGrory and some fine goalkeeping by Andy Coleman earned Glenavon a 2-1 win over Glentoran in the League Cup quarter-finals.
McGrory poked in the opener in the 10th minute after Kris Lindsay had headed down Marc Brown's ball from the right.
Glenavon went two up early in the second half when Guy Bates ran clear to set up McGrory who had the simple task of side-footing in.
Jimmy Callacher's header gave Glentoran hope but they could not equalise.
"We are absolutely ecstatic. We had a lot of players out last Saturday when Crusaders taught us a lesson," said keeper Coleman.
"But the experienced heads were back tonight and it showed.
"This is massive for the club. It is a first semi-final in 11 years and the fans deserve it.
"A club this size should be in more."