Arsenal need to be ruthless to secure a win against Sporting and snap their negative run of form away from home in the Champions League, manager Mikel Arteta said ahead of Tuesday's clash.

Winless in their last four European outings, Arsenal arrive in Portugal following a 1-0 defeat against Inter Milan at San Siro earlier this month.

Arteta's side currently sit 12th in the new Champions League 36-team format, where the top eight teams qualify automatically for the last 16, and the next 16 enter a two-legged playoff to join them.

The Spaniard acknowledged that improving their away form is key to his team's chances in Europe's top-tier club competition.

"It's certainly something we have to improve. We have the right steps, and looking back at the way we played against Inter, we dominated the game and should have won," Arteta told a news conference on Monday.

"But the reality is you have to make it happen, and we didn't. Those steps are what we need to take next - be ruthless and much more efficient in the opposition box.

"We wanted to be higher (in the standings), but it's the position we are in right now.

"We have to play in a way that's going to give us a chance to win the game and fight to do it as quickly as possible. Tomorrow we have a great opportunity to do that."

It will be the seventh meeting between Sporting and Arsenal in European competition. The Portuguese side are still looking for their first victory over the Gunners (D4 L2), though each of their last three meetings have ended level.

Sporting, who thrashed Manchester City 4-1 in their last outing, are enjoying an outstanding campaign, remaining unbeaten in second place with 10 points. However, they are now without former manager Ruben Amorim, who has departed to Manchester United.

Arteta acknowledged the Portuguese champions pose a major challenge for Arsenal but also offer an opportunity for a morale-boosting triumph.

"The run they are on is incredible, which tells you it's not only about their qualities but their ambition and the team energy they have. That's the great challenge we have," he said.

"To come here tomorrow, make a statement, and show that we are capable against this kind of opponent by being ourselves and winning the game."