Arsenal manager Arsene Wenger said Yaya Sanogo and Joel Campbell would be given chances to shine this season after both youngsters impressed in the 5-1 friendly demolition of Benfica.

Sanogo, a 2013 signing from Auxerre, scored four times in Saturday's Emirates Cup encounter, while Campbell, who has spent the last three seasons out on loan, scored once and supplied one assist.

Sanogo, 21, endured a difficult maiden campaign at the Emirates Stadium, failing to score in 14 appearances.

Wenger persisted with him, however, handing him surprise starts against Bayern Munich in the Champions League and Wigan Athletic in the FA Cup semi-finals, and he feels 2014-15 could be his breakthrough season.

"Football surprises you always. Not only you, but me as well," he told journalists at the Emirates Stadium. "Sanogo was injured for basically two years before he came to us. If you look at his goal-scoring record before he got injured, it is quite frightening.

"For a while when he came back last season, he could not score. But I think it was a mental block. You could see when he scored the first goal today (Saturday), suddenly they can rain in.

"He has a big future here, of course. He is 21 years old."

Campbell, 22, joined Arsenal in 2011, but work-permit issues saw him successively loaned out to Lorient, Real Betis and Olympiakos.

The left-footed forward excelled at Olympiakos last term before catching the eye with Costa Rica at the World Cup in Brazil, and Wenger heralded his effervescent display against the Portuguese champions.

"Campbell has done very well," said the Frenchman. "I like the way he plays. He's good on the ball and he's creative and collective as well. He has a good balance between individual skill and collective attitude. That's not easy to find." 

Asked if Campbell would be allowed to leave the club on loan again, Wenger replied: "No. There's no reason to let him go. At the moment I want to keep him."