Two shocking mistakes from Branislav Ivanovic gifted goals to Michu and Danny Graham, leaving Chelsea with a huge task to overturn the deficit at the Liberty Stadium in a fortnight.
Chelsea failed to convert dominance into goals, although Benitez was unhappy that Demba Ba's strike in added time was ruled out for offside.
Benitez said: "The team are doing well. You can lose a game and then analyse it, but if you play this game 10 times maybe you will win nine of them.
"I think the team were doing really well, had a lot of chances and could have scored two or three in the first half but we made two mistakes and paid for them.
"I can see any player making mistakes and it's not an issue. It's about trying to do things afterwards, and Ivanovic tried to do his best. We carried on and tried to do the right things."
Benitez insisted that Ba's late goal should have stood, and added: "The goal was a goal, he was level."