Swansea boss Brendan Rodgers was disappointed with his his side's aerial defending in their 2-0 defeat to Stoke City at the Britannia Stadium on Sunday.
Both goals came from headers, first through Matthew Upson from a Matthew Etherington corner kick and then Peter Crouch from a Ryan Shotton throw-in.
Speaking to Sky Sports after the loss, Rodgers said: "We are obviously disappointed. Their quality into the box was good, their delivery was good but it was the middle of the goal.
"We work with zones and someone should have been there to head away in that zone. The second one we gave away a needless throw-in. The ball came in and we never dealt with it."
In October, the Swans beat Tony Pulis's men 2-0 and on that occasion, they managed to limit the Potters' threat from set pieces.
The Scotsman added: "We've played against Stoke before earlier on in the season and dealt very well with it and won the game 2-0.
"So today it was disappointing, especially playing so well for large parts of the game.
"We had a chance to go 1-0 up. We created a chance early on in the game and obviously didn't take the chance."
Goalkeeper Michel Vorm did not play in the defeat, missing out for the first time in the Premier League this season.
