Pc Mary Ellen Bettley-Smith, 31, also said she was “terrified” during an incident in which Pc Benjamin Monk is alleged to have murdered the former Aston Villa star in Telford, in August 2016.
The Crown alleges West Mercia Police probationary constable Bettley-Smith, who denies assault, acted unlawfully after Mr Atkinson had been Tasered to the ground by Monk.
Pc Monk, who accepts he kicked Mr Atkinson twice in the head, denies murder and manslaughter.
Giving evidence in the sixth week of a trial at Birmingham Crown Court, Bettley-Smith said Atkinson, who also played for Sheffield Wednesday and Ipswich Town, was “probably the angriest” person she had ever seen after he emerged from the door of his father’s home in Meadow Close, Trench.
Bettley-Smith, who pressed an emergency alarm after the first of three Taser cartridges had no effect on Atkinson, denied acting out of anger or because Monk had told her to use a baton.
Telling the court she used a baton “to try to gain control of the situation” because 48-year-old Atkinson was trying to get back to his feet, Bettley-Smith said: “I was very scared at what he could do to Ben and myself if he did get up.
“As we got close to the driveway I recall that I could hear shouting.
“I recall that he opened the front door and was there, this huge figure. He appeared very, very angry – probably the angriest person I have ever seen in my life.”
Asked by her counsel Richard Smith QC to explain what made her think Atkinson was angry, Bettley-Smith added: “It was everything. I remember his eyes bulging out of his head. His chest was puffed up … his stance made me think he was ready to fight.
“When he initially came out of the door I was very taken aback at just how angry he was.
“Immediately, my threat level went through the roof – pretty much as soon as he came out of that front door, I felt terrified.”
Giving her account of the events when a Taser was first fired by Monk, Bettley-Smith, a social work graduate who joined the West Mercia force in February 2015, said: “I had no awareness that the Taser could fail.
“My understanding was that you fired a Taser and the person was stopped in their tracks.”
Bettley-Smith said she had pressed an emergency alarm button for urgent help – for the first time in her career – because she believed the situation at the scene to be life-threatening.
“That was exactly how I felt,” she told the court. “In those moments I was petrified.
“I said in my interview that my life flashed before my eyes and that is no exaggeration – I was absolutely terrified.
“I wanted everybody and anybody to get there as soon as possible to help us.”
Asked if she had been hesitant to follow Atkinson when he went back towards his father’s home, Bettley-Smith said: “I didn’t want to have to go back and face this man again after running away, but I had to override my fear for myself because I was massively concerned about whoever was in the house.”
After Atkinson was Tasered for a third time and went straight down, Bettley-Smith said she delivered three blows with her baton, aiming at his thighs.
The officer continued: “I went over to where Mr Atkinson was on the floor. He was trying to pull out what I perceived to be the wires out of his chest.
“As I looked over at Mr Atkinson I thought he was trying to get up.
“It was at this point when I decided I needed to strike Mr Atkinson with my baton. Unless it was absolutely necessary, I would never have used my baton that night.
“I struck him to prevent him from getting up and protect myself and Ben.
“If he was successful in getting up, I genuinely thought he would seriously hurt me.”
The trial continues.