Martin Jol’s side face Leicester City in the Capital One Cup Fourth Round on Tuesday, before hosting Manchester United at the Cottage on Saturday in the league.
And Ruiz admits Fulham will need to turn in a much-improved display in those games to the one at St Mary’s on Saturday as first-half headers from Rickie Lambert and Jay Rodriguez earned the Saints a deserved three points.
“Southampton played well,” Ruiz told the official website. “We had a plan but once they scored the first goal it was difficult to find a way back into the match. They deserved the win but now we have to pick ourselves up and look towards the next match.”
The Whites had gone into the clash with the Saints full of confidence after back-to-back wins – but they never really got going at St Mary’s, failing to test Artur Boruc in the hosts’ goal.
“After winning two games in a row, we wanted to continue that at Southampton,” continued Ruiz. “We weren’t able to do it and we were all disappointed with the display.
“The most frustrating thing was not testing their goalkeeper. We should have done more but Southampton have only conceded three goals this season and they’re very strong defensively. They’re in good shape and full of confidence but we need to try and forget about it now and concentrate on the next match.
“We’ve got two games coming up quickly and it will be a tough week. We want to qualify for the next round of the cup and then take on Manchester United in a good frame of mind.”
Ruiz passed a late fitness test to feature at St Mary’s and the Costa Rican added: “I still have some problems with my back and we’re working on that. It’s getting better - hopefully in the next couple of weeks it will be 100 per cent.”