Ghana striker Jordan Ayew's big miss against Arsenal has been described as his manager Paul Clement as unfortunate.
According to Clement, they could have defeated Arsenal if Ayew had increased their tally before the break in their game at the Emirates Stadium last Saturday.
The Swans suffered a 2-1 defeat against the Gunners eventually in a game manager Clement felt was theirs to lose.
“It [Ayew's chance] was a big chance and 2-0 at half-time would have made it a totally different situation, but those are the fine margins we are dealing with," Lambert said.
“If that ball had gone in, it could have been different [and we would've won the game].
“The first goal we conceded was fortunate for them because the ball had bounced off a few of our defenders before fallen to their wing-back.
“I am more disappointed with the second goal. We did not get the details right in that, we were too open and made some mistakes.
“I think we were worth a point, we played well in the first half. You always know it is going to be a tough task coming here against a strong attacking side with quick combinations in and around the box."
He added: “We knew we would need to be focused for the whole game and in the first half we played well and took our chance on the counter-attack, which is where we thought we would get our opportunities.
It was just that period after half-time where we did not get our details right, we did that so well in the first half."
Ayew lasted 81 minutes before being replaced by Luciano Narsingh.
Swansea are 17th on the table with eight points and will welcome Brighton and Hove Albion next weekend before a trip to Burnley.