Chelsea manager Antonio Conte said Alexis Sanchez "had his hands attached to the ball" before scoring Arsenal's opening goal in their 2-1 win in Saturday's FA Cup final.
After Sanchez scored, confusion reigned for 40 seconds as referee Anthony Taylor went to speak to the linesman before awarding the goal -- seemingly unaware of Sanchez's handball in the build-up.
And after Arsenal lifted the trophy, Conte said he thought Sanchez's goal "was very strange."
"The first half we didn't start well, we didn't have the right approach and we suffered in first 25 minutes," Conte told the BBC. "We started to play better in the second half and the red card was decisive.
"I didn't see the incident on the TV and it was difficult to understand. The first goal, the player had his hands attached to the ball with two hands. Offside or not is not important.
"Arsenal started very well with great determination. They surprised us a bit but I repeat, our first 25 minutes weren't good."
It got more difficult for Chelsea as Victor Moses was sent off for a second yellow card in the second half, just as Chelsea had shown intent in pressing for an equaliser.
"At our best moment, the referee decided to give the red card," Conte said. "There is disappointment for the final result but it can happen and there was a lot of pressure. Victor Moses has been good and played an important season.
"Our season was incredible to win the league in this way, it was great but now its important to look forward and to restart."
Chelsea goalkeeper Thibaut Courtois said the team were disappointed with the result and agreed with his manager about Arsenal's opener.
"The first goal should never have been allowed -- it was clearly a hand ball and then Ramsey was offside because he he was interfering in play.
"After that goal, we tried to play but they deserved it.
"Then we went down to 10 men and the red card was correct. Victor Moses doesn't need to apologise.
Courtois was also not surprised by the result and acknowledged that with Arsenal's recent form, his team were expecting a challenging final.
"When you score, you get momentum and can build on that. We tried but obviously not enough.
"If you play final you build up to that and maybe they did that more because we already won the league."