Arsenal finished some 13 points behind Chelsea in the Premier League last season, but 11 points of that lead was built up in the opening six games as Wenger’s men won only twice.
“It was the fact they started strong and we didn’t,” said Wenger of the gap between the two clubs.
“They were more stable than us defensively, at the start of the season especially.
“After six games, we were 11 points behind Chelsea. We finished 13 points behind Chelsea. That means after six games the decision was made.
“That is what they had – a strong start while we had a slow start.”
Wenger believes there were mitigating circumstances for the poor start last season but accepts there can be no such excuses this time around.
“There were reasons, that’s for sure,” added the Frenchman. “We lost Giroud, Koscielny and Ozil for four months, right from the start.
“We had Welbeck on August 31. This season, it is different.”
Jack Wilshere has said Arsenal are in a “really strong position” going into the Premier League kick-off next weekend, but Paul Merson believes his former club will fall short in the title race once again if they end the transfer window with Francis Coquelin as their only holding midfielder.
“Arsenal will not win the title with just Coquelin in the defensive midfield role,” Merson said in the Daily Star.
“They are talking about them putting in a bid for Busquets – that would be a massive signing.
“Arsenal need an experienced player, especially when you get to the latter stages of the Champions League. You’ve got to remember that Coquelin was on loan last season at Charlton Athletic – now he is on the Arsenal team sheet.”