Southampton manager Ronald Koeman is impressed at how well Fraser Forster has fitted back into the team since coming back from injury.
The Saints goalkeeper has kept five clean sheets in a row since coming back from a serious knee injury, which kept him out for nearly 10 months.
"If the player is out for nine or 10 months then you are not sure how they will come back or you are not sure if they will go straight in at that level -- but it has surprised me, that he was out for a long time from the start.
"It is a great credit to the player and the medical staff because the player was back in full condition."
He added: "Of course, Fraser has had an impact in those five clean sheets but in my opinion it is the whole defensive line-up -- and defending starts in front.
"The whole team needs to work hard and the whole team needs to do good pressing and we have fantastic organisation against West Ham because West Ham didn't create any chances."
Southampton face a Swansea side who sit just five points above the relegation zone but Koeman knows the different system Francesco Guidolin plays compared to former manager Garry Monk will mean his team will have to play a different system than the one they employed in the 3-1 win in September when Monk was in charge.
He said: They play a different system -- they would always play a 4-3-3 system.
"It was good football, building from the back - similar to how we play, but with the new manager you can expect changes in the team.
"[They are] playing a 4-4-2 system now, they have new players, it is a different manager, it is a different style of play.
"I think you can play against every system with three at the back but in detail you have to change your tactics... if you play with two in front I play three at the back.
"We have enough information to play them this Saturday."