Manager Arsene Wenger said Arsenal are more united since the transfer window closed at the start of September as the Londoners look to extend their unbeaten streak to four matches.
It was a turbulent time for Arsenal before the transfer window shut following a 4-0 rout at Premier League rivals Liverpool amid uncertainty over Alexis Sanchez's future.
Sanchez was tipped to join Manchester City but the Chilean star stayed at the Emirates Stadium, though Alex Oxlade-Chamberlain and Kieran Gibbs moved on.
"It feels like a different team. You see the way we play football," Wenger said ahead of Sunday's hosting of Brighton and Hove Albion.
"You need to have a united group to do that. The weight of the transfer market was much heavier than internationals.
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"I put [our improvement] down to the fact that we realised what we produced was not good enough. But that was a special day for us: it was just before the transfer window closed and just before an international break.
"Overall we stayed united and responded on the pitch."
Arsenal are seventh in the standings, nine points adrift of City and Manchester United.