Last season’s treble-winners head to London for Tuesday’s first leg having gone 32 matches unbeaten in all competitions – a run which has seen them break the club record set under Pep Guardiola.
Arsenal were held to a 0-0 draw by Hull City in the FA Cup fifth round on Saturday – the fourth time they have failed to score at home in 2016 – despite dominating possession, and Wenger wants a more clinical edge in attack when the European champions come calling.
“Of course, it’s an exciting game,” he said. “We were the favourites [Saturday] but we won’t be on Tuesday.
“We’ll need great solidarity because we’ll need to defend well, and make the maximum of our possession, which we didn’t do today.”
Arsenal have already beaten one of the tournament favourites this season, having defeated Guardiola’s Bayern Munich 2-0 during the group stage, but Barca’s form makes for daunting reading for the Gunners.
The holders emerged unbeaten from the group stage and have been in stunning form domestically, winning all but two of their last 16 Liga and Copa del Rey matches and failing to score just once in that time, away to Espanyol in January.
Barca were given a tough test at Las Palmas on Saturday before ultimately winning 2-1 thanks to goals from Luis Suarez and Neymar, with Luis Enrique expecting another difficult encounter against Arsenal.
“We’re starting a game of 180 minutes. I’m sure they will be a difficult opponent, with enough quality to create problems for us,” he said. “It will be tough, just like any knockout.”
Wenger has passed Mesut Ozil fit after he was rested for the Hull game due to illness, while Aaron Ramsey, Olivier Giroud and former Barca forward Alexis Sanchez are all likely to be back in the starting line-up.
Francis Coquelin should also return, though the game comes too early for Jack Wilshere (leg) and Santi Cazorla (knee).
Arda Turan is suspended and Rafinha remains out with a knee injury, but Barca have an otherwise strong squad to take to London, which includes former Arsenal captain Thomas Vermaelen.