Anna Haitana was so desperate for a cigarette, she plunged a boning knife into her partner, collapsing his lung.
The 58-year-old struck the man with such force, the 15cm long blade went straight through his leather vest and embedded into his back.
He screamed out in pain and collapsed onto the ground, the New Plymouth District Court was told on Thursday.
Occupants at the Waitara, Taranaki, home rushed to help the man who was yelling for the knife to be pulled out of him.
Moments before the afternoon attack on November 1 last year, Haitana and her partner had been drinking alcohol together at the Waitara address, where they resided on the section in a portacom cabin.
They had begun arguing and the man, tired of listening to Haitana's demands, walked away from her.
He stood in the driveway drinking a beer with his back towards her while she went into their cabin and located the boning knife.
Enraged, Haitana approached the man from behind and stabbed him with the weapon, a Crown summary of facts stated.
A short time later, police arrived at the address and arrested her.
In explanation, she told officers "I only wanted a cigarette."
Meanwhile, the man was transported to the hospital by ambulance for emergency surgery.
He had received a puncture wound so deep the knife had penetrated his lung, causing it to collapse.
In court, Crown prosecutor Laura Blencowe withdrew a charge of possessing an offensive weapon, and amended a charge of wounding with intent to cause grievous bodily harm to one of wounding with intent to injure.
Following that, Haitana entered a guilty plea to the single charge, which carries a maximum penalty of seven years' imprisonment.
Judge Lynne Harrison issued Haitana with her first-strike warning.
The matter was referred to restorative justice and a pre-sentence report was ordered.
Haitana will be sentenced on May 24.