Michael Enzanga, of Ashfield Road in Tottenham, north London, was likened to a ‘caged animal fighting for his life’ as he plunged a knife into the back of PC Russell Turner in Stamshaw Park on February 21.
Following a two-week trial at Portsmouth Crown Court a jury found him guilty of causing grevious bodily harm with intent.
He was also convicted of four charges of possessing crack cocaine and diamorphine, with intent to supply the class A drugs on February 20 and 21, and a charge of possessing criminal property, namely a stash of money.
PC Turner had been looking into reports of drug dealing in the area with colleague PC Claire Parry. Both officers were in plain-clothes at the time.
The jury took just 45 minutes to find Enzanga guilty.
Enzanga is due to be sentenced on October 4.
Earlier in the trial, the court heard that PC Turner and PC Parry had approached Enzanga, then aged 19, near an adventure playground in the city.
PC Turner had his warrant card out and identified his colleague and himself as police officers when Enzanga tried to run away and a struggle broke out.
PC Parry said the defendant was like a ‘caged animal fighting for his life’ when he attacked PC Turner.
She said Enzanga seemed to do the punching action ‘several times’ and that ‘from what I could see of Russ he was stabbed at least twice’.
In a taped interview played to the jury, PC Turner said the thuds to his body seemed like ‘what I imagine someone like Mike Tyson banging and hitting me hard in the back’.
He said he saw a black-handled knife with a sharp silver blade that was about 5in to 6in long.
Enzanga, who was homeless and sleeping in the park at the time of the incident, had claimed he was running away from a pair of attackers on February 21, when he ‘ended up getting chased by the police’.
A carrier bag containing 60 wraps of crack cocaine or heroin was left at the fight scene and police later recovered a silver kitchen knife, the jury was told.
Enzanga was also found to be in possession of nearly £1,000, which he previously said came from monthly benefits and borrowing cash from friends.
The court heard he has previous convictions for possession of a blade and handling of class A drugs.
The jury also heard that after stabbing the officer, Enzanga fled in the direction of a block of flats called Hastings House but was seen by members of the public and spotted on CCTV carrying a knife before he was Tasered by officers as he fled.
He was spotted climbing garden walls to escape.
Police fired a Taser but he continued to flee until he was eventually arrested after being found hiding under a tarpaulin in a back garden.