Wenger accepts Chelsea were "impressive", yet maintains finding that consistency over the entire nine months of the season is the key to success.
"I watched the first half, and then stopped watching because I felt the game was over," Wenger said.
"Chelsea were very good, but Portsmouth had a bad day at the office, that can happen to anybody. Before they could even get into the game, it was already over for them.
"However, Chelsea were impressive - but on one game you cannot assess too much.
"Chelsea will be one of the super candidates to fight for the title, but I feel we have enough to fight with them."