"I always want my champion to win hands down," Le Pen senior said of yesterday's debate viewed by more than 16 million people.
But the 88-year-old deemed the duel a "draw", saying his daughter - who kicked him out of her National Front (FN) party in 2015 - "perhaps did not rise to the occasion."
Speaking on French radio, he blamed the candidate's advisers for underestimating a "very solid" Macron, wrongly "hoping for a collapse or a psychological meltdown."
Marine Le Pen has sought to purge the FN of associations with her xenophobic, anti-Semitic father, who co-founded the party in 1972.
When Le Pen senior was a shock finalist in France's 2002 election, his rival Jacques Chirac refused to debate him out of fear of "normalising hate and intolerance".
He has repeatedly called the Nazi gas chambers a "detail" of history.