Arsenal were crushed 8-2 at Manchester United in their last game on August 28 and with just one point from their opening three games are currently 17th in the 20-team table.
Wenger, though, told the club's official website: "We were very disappointed [after losing to United] and we were absolutely down after the game but putting things into perspective, we were really weakened on the day.
"We had a very demanding game on the Wednesday against Udinese and then conceded four goals in the last 20 minutes when we were down to ten men.
"Of course it was difficult, but maybe the international break came at a good time. In between we could buy some players and could get some players back from injury. The real start of the season, where we can get the whole squad together, is now."
"What really incited me (to buy) was knowing that [Jack] Wilshere will be out for longer than expected, that [Thomas] Vermaelen needed surgery, that [Kieran] Gibbs having the whole season on his shoulders at left back with [Armand] Traore leaving would be very difficult.
"With [Nicklas] Bendtner going out the possibility to buy another striker was also there.
"I wanted as well some more experience in the squad because on the bench at Manchester United we were very, very young. In a game of this stature of course it's very difficult for the players."
"Swansea are a good side who play good football, building out from the back," said Wenger. "Possession-wise they are very good, they are a team who plays football which is suited to the Premier League and that is why we must have a good performance."
