Barkley, who had not made a competitive appearance this season due to his lengthy recovery from a serious hamstring injury, came on after just 30 minutes when Willian's hamstring tweak forced Antonio Conte into an early substitution.

The score was 1-1 when Barkley entered the field after Antonio Rudiger's freakish own goal had cancelled out Eden Hazard's early opener, but Granit Xhaka poked in the winning goal for Arsenal on the hour mark, capitalising on another unwitting deflection from the Germany international.

After the match Conte pointed to Willian's exit as "decisive" and a visibly rusty Barkley was unable to make a significant impact on proceedings, but Azpilicueta is confident that the former Everton man will go from strength to strength once he gets back into the rhythm of playing.

"We know that he is coming back from a long injury and he has only played for the under-23s but he came straight on without a warm-up and seems on the right path," Azpilicueta said.

"He is coming from a seven-month injury and is with a new club and a new team. What I see in training is him working very hard to work with the team and I am sure he will be very important.

"Now in the next six or eight games we have the next rounds of the FA Cup, we have the Champions League and we have the Premier League. We have to keep pushing and we need everybody 120 percent."

Conte lamented the lack of options on his substitutes' bench in his post-match media duties, and the Chelsea hierarchy are working hard to bolster his squad in what remains of the January transfer window.

Roma left-back Emerson Palmieri is expected to become the Blues' second signing of the month, while talks are ongoing over a move for his teammate Edin Dzeko. Several of Chelsea's domestic rivals have already strengthened, but Azpilicueta believes there is still time to acquire the reinforcements required.

"I am sure we are working on it the same as every team," he added. "We have signed Ross and I am sure we are trying to get the players who can improve the team. But we still have a few days to go -- all those other teams have just done their business already."