Mary Coulter, 76, suffered broken arms, head injuries and deep cuts to her face when her house in Wishaw, North Lanarkshire, was broken into in the early hours of March 22.
One of the blows landed on her by Derek Clark all but sliced her face off, a court heard.
Clark, 32 – who was high on cocaine at the time of the attack – previously admitted attempting to murder Mrs Coulter at her home in Overtown.
He and two other men had forced their way into the elderly woman's home at about 4am. They werehunting for her son Ronnie Coulter, who Clark claimed was terrorising his family.
A judge at the High Court in Glasgow yesterday jailed Clark for 10 years for trying to kill the pensioner, and imposed a further five years behind bars for a separate assault on Grant Murdoch later that same day.
Mr Murdoch was tortured and dumped in woods amid claims that he owed Clark money.
Clark's five-year jail term will run consecutively to his 10-year term. He will also be supervised for a further five years, under an extended sentence, following his release from jail, the judge said.
Co-accused Richard Parvin, 29, was sentenced to 10 years for conspiracy to assault in relation to the incident and for his role in the subsequent assault.
Darryl Finnie, 27, was given four years behind bars for conspiracy to assault.
Passing sentence, Lord Stewart said: "The agreed narrative confirms Richard Parvin and Darryl Finnie knew Derek Clark had what is called 'a large knife'.
"The nature of the weapon could help to explain a number of things, including the nature and severity of the injuries inflicted."
Addressing Clark specifically, Lord Stewart said: "You attempted to murder the mother of the intended victim with the weapon you were carrying and the severe injuries you inflicted have lasting consequences."
He went on: "The attack on 76-year-old Mrs Coulter represents an act of unbridled savagery. One blow all but sliced her face off.
"Grant Murdoch was attacked by you with apparently calculated savagery."
Detective Superintendent Clark Cuzen, of Strathclyde Police, said: "I hope the fact these men are being sent to prison will offer Mrs Coulter and her family some consolation."
Ronnie Coulter, his nephew Andrew Coulter and David Montgomery were cleared of murdering Asian waiter Surjit Singh Chokar in Overtown 1998.
But the Crown Office is taking a fresh look at the case under Scotland's new double jeopardy laws.