Graeme McLaren, 47, skewered James Small with the walking aid leaving him with horrific internal injuries in June this year.
Mr Small, who died days later in his flat, was assaulted after McLaren allegedly caught him semi-naked with a female friend.
Yesterday a jury at the High Court in Glasgow unanimously found McLaren guilty of murder.
Judge Rita Rae QC told him: "It's difficult to comprehend the level of brutality that must have been involved in inflicting serious injuries on a defenceless old man."
McLaren faces a life sentence and Judge Rae will determine how long he must spend behind bars before being eligible for parole today.
McLaren, 47, of Greenock, denied attacking his neighbour Mr Small. The gruesome assault occurred at Mr Small's flat in Weir Street, Greenock.