I'm just having a look at this debate from last year. Dan Barker certainly put up a more impressive performance than George Pell, but fine - Pell doesn't have to have the sort of personality that wins people over in debate. These kinds of debates don't necessarily prove a great deal. They're largely beauty contests. An articulate, physically attractive, well-coached actor would "win" such a debate each time.
That said, Pell certainly resorts to a lot of obfuscating and fillibustering. It's not a lot of fun to watch. He doesn't have a talent for this kind of debate. He's no William Lane Craig - though he did have a pretty good support squad there.
More importantly, however, I'm amazed that he simply denies that Antony Flew ended up becoming a kind of deist rather than a full-fledged theist, and that he relies on the title of Flew's book - There Is A God - as evidence. Yes, a deist is also going to say "There is a God [of sorts]" (leaving aside the fact that titles are chosen largely on commercial grounds and don't necessarily give much indication of the detailed thesis).
Flew believed what he believed, and you just have to accept it. You don't get to make up your own facts.