The 2-2 draw in the FA Cup fourth round clash at Griffin Park means the Blues are facing further fixture congestion at a defining time in their season.
Some of Rafael Benitez's men could potentially play nine times between now and March as they vie to challenge in the Europa League as well as domestically.
Cahill told the Fulham Chronicle: "We needed to dig in and just get the result we needed - obviously we wanted the win - to at least take it back to the Bridge.
"We were sloppy and off the pace. Second half was better and we showed good character."
The 27-year-old admitted the Blues are facing a testing time with upcoming games in the Premier League, FA Cup and Europa League.
He added: "It's not ideal. There are that many games at the moment it feels like you're only just recovering and then there is another game again."