Jermain Defoe admitted he didn't undergo a medical before completing his move to Pompey.
The striker signed for the Blues on loan from Tottenham Hotspur on January transfer deadline day in 2008.
After Benjani departed Fratton Park for Manchester City, boss Harry Redknapp was in a rush to complete the deal for Defoe.
As a result, he allowed the England international to skip his medical in order to get the transfer rubber-stamped before the window closed.
Defoe told Sky Sports: 'When I went to Portsmouth, it was deadline day.
'Benjani went to Man City and I went to Portsmouth with Harry.
'I was at my mum's house and had to rush to Portsmouth.
'Harry was like "don't bother about the medical, you're fit. You're fine!"
'He knew me from a kid (at West Ham), so he was like "come on JD, you've just got to get down and score some goals. You don't need a medical, you're young and fit".'
Defoe’s eight goals in 12 appearances helped Pompey to an eighth-place finish in the Premier League that season.
He was, however, cup-tied for the Blues' FA Cup triumph.
Defoe made his move to Fratton Park permanent the following summer.
He registered nine times from 24 matches during the first half of the 2008-09 campaign before he followed Redknapp and returned Spurs in the January transfer window.