Daryl Fordyce equalised with a minute left to deny Glenavon a surprise victory over the Premiership champions.
Linfield's Brian McCaul sent an over-kick wide in a poor first-half with all the drama coming after the break.
Glenavon keeper Andy Coleman saved Peter Thompson's penalty before Ciaran Martyn's 77th minute shot managed to squeeze past Alan Blayney.
Fordyce hit the bottom corner to earn a draw but the Blues are now 14 points behind leaders Cliftonville.
Former Linfield defender Kris Lindsay fouled Thompson for the penalty but the forward fired his spot-kick straight at Coleman.
Glenavon survived a goalmouth scramble from a corner before taking the lead as Martyn scored his first goal for the Lurgan Blues, although Blayney should have kept his shot out.
Substitute Fordyce came to Linfield's rescue with a low strike finding the net before Sean McCashin squandered two headed chances to win the game for Glenavon in the dying seconds.
Linfield have lost further ground to the Reds while Glenavon are now six points clear of bottom spot.