Advocaat, who engineered a third successive escape at the end of last season, departed just eight games into the new league campaign with the club having collected only three points and although they remain inside the drop zone heading into Sunday's clash with Arsenal, their performances have improved dramatically under Sam Allardyce.
Defoe told the Journal: "It's happened because of the start of the season
We just weren't good enough and we weren't fit enough.
"If you look at the fitness stats now - the running stats and the high intensity stats, that side of it - we were so far off, so far off where we are now
Look at the [opening day] game against Leicester - we were blown away
It was difficult.
"Now it's like a different team
The first thing the manager [Allardyce] said when he came in, we had a meeting and he said, 'You're not fit enough.' He said, 'I'll get you fit and that's all you need' because we've got top players and internationals.
"But if you can't run, how are you meant to perform for 95 minutes?"
Allardyce's arrival proved to be good news for Defoe in particular as he eventually persuaded the new man he could score goals from a central position after being employed largely as a wide-man under Advocaat, and he goes into the weekend with 16 to his name.
Source : PA
Source: PA