He didn't think Anakin to be much of a threat - definitely having no idea about anything he may have dealt with later. Any Jedi could pose a challenge but not one that couldn't be overcome, he thought.

"Sure, you owe me big time."

Maybe it had been his own mistake for not trusting his first instincts better but hindsight and all...

"If you make it up to me, we can call it even."