Swans failed to follow up Thursday's Europa League win against St Gallen with another positive result, Michu and Wilfried Bony were denied by fine Artur Boruc saves while Saints Academy graduate Nathan Dyer hit the inside of a post before half-time.
"I don't know if frustration's the right word, but I think there are always positives and negatives in every game," Laudrup said.
"Before we started this season we said it would be difficult for the team and we've seen a lot of cases around Europe of teams who have to play on Sundays.
"I can only say we are doing well, and are playing well in all the games after midweeks.
"This was the seventh game in 20 days. I thought it could be some players tired. You play every three days, but I really didn't see that.
"It's true Southampton were the best team in the first 10 minutes, but since the goal I think we dominated the whole game.
"The second half we dominated from the first to last minute, but maybe not creating the same number of chances."