Debra Reynolds choked back tears at the funeral, held in Mossley Methodist Church in Newtownabbey, as she paid tribute to her best friend and soul mate Philippa Reynolds.
"Never in my life would I think that I had to be the one saying goodbye," she said.
Constable Reynolds, 27, was a back seat passenger in the unmarked police car that was struck by the jeep in Londonderry in the early hours of Saturday morning.
Two men have been charged in connection with her death.
PSNI Chief Constable Matt Baggott said she was a superb police officer, the best of the best.
He said she was compassionate and caring and wanted to make lives better.
Speaking ahead of Miss Reynolds’ funeral, the PSNI Chief Constable said it was a day of “profound sadness and sorrow”.
"She was the embodiment of what policing aspires too. She wanted to make Londonderry/Derry a finer and safer place, working towards building peace in that city," Mr Baggott said:
Miss Reynolds died instantly when the patrol car she was a rear seat passenger in was struck by a stolen vehicle in Londonderry in the early hours of Saturday.
The young officer, from Nutts Corner, Co Antrim, originally qualified as a teacher before leaving the profession to accept a place in the police training college in February 2011.
Mr Baggott said he had been the convening officer on the day of Miss Reynolds’ PSNI graduation.
“The Police Service of Northern Ireland is undoubtedly the finest police force in the world, and Philippa was undoubtedly the best of the best,” said Mr Baggott
“She was kind, she was caring, she was courageous when necessary, she was compassionate.”
Mr Baggott said Miss Reynolds had made a huge impression on her colleagues and the public during her short spell in the service.
“She was part of the story of peace building in Derry/Londonderry. Peace comes when people show kindness, peace comes when people show caring, and Philippa was part of that story,” he said.
“I just want to say thank you to the Reynolds family for giving Philippa to us.”
Mr Baggott said Philippa was both “impartial” and “inspirational” and talked about meeting her family on Tuesday.
“I can see from her family why Philippa was so good at what she was doing, why she was such a fantastic police officer” he said.
“Philippa had a wonderful quality of humility, she just got on with it.”
Miss Reynolds’ district commander, Chief Superintendent Stephen Cargin, described the officer as “a loving daughter, a sister, a best friend”.
He said Miss Reynolds’ typified what it meant to serve the community as a police officer.
Both men thanked the public for their support since the tragedy.
“I’ve been overwhelmed by the support.,” said Mr Cargin.
“Her parents said to me on Sunday ‘we hope something good comes out of this’.
“Something good has come out of it - communities have come together, communities are uniting behind us as a police service, uniting together and supporting us as a police service. So something really powerful has come out of this.”
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