The Gunners boss says a spell in late February and early March was what saw his side's title challenge crumble.
Arsene Wenger has told beIN Sports, as quoted by the London Evening Standard, that a four-day period at the end of February and the start of March was the time which was "the killer" for the Gunners' title challenge.
Arsenal had been top of the Premier League at the start of 2016, and were neck-and-neck with eventual champions Leicester City in late January and looking good for a sustained push to win a first championship in 12 years.
However, a run of poor form saw them suffer a four-match winless streak, during which they lost at home to Chelsea and drew at Liverpool, and be held to goalless draws by Stoke City and Southampton.
They looked to have got themselves back on track after that disappointment with back-to-back wins over Bournemouth, and the dramatic last-gasp victory over Leicester on Valentine's Day.
That saw Wenger's side just two points behind the Foxes, but the Gunners then suffered defeat at Manchester United and a disastrous home loss to Swansea City to fall to six points off the pace.
Wenger admitted he is still disappointed with the failed title challenge despite ultimately finishing in second, and suggested that double loss to United and the Swans - which came in the space of just four days - was the killer blow for their hopes.
The French boss told beIN Sports, as quoted by the Standard: "We are disappointed from not having won the Premier League. We are very disappointed because we felt for a long time that we could win the league but we also knew we had very difficult away games and they would be the real test for us.
"At the real important moment of the season we lost at [Manchester] United and at home to Swansea. That was the killer for us. What hurts most is not to be first."
Though the wait for a first title since the famous 'Invincibles' triumph of 2003-04 goes on, there was something to shout about for Gunners fans on the final day of the season, as they leapfrogged arch-rivals Tottenham Hotspur at the last to finish in second.
That extended their record of finishing above their neighbours to a 21st season, but that is unlikely to remain enough for the supporters who are hungry to see their side at the top of the English game once again.