Coutinho, 25, made a €160million move to Camp Nou earlier this month in a blow to Liverpool's chances of securing a top-four finish in the Premier League.
But Oxlade-Chamberlain believes there is enough depth in Jurgen Klopp's squad to deal with the departure of the Brazilian.
"When Phil didn't play in some games we still played great football and we still have amazing players who can score goals – the likes of Mo [Salah], Sadio [Mane], Roberto [Firmino] and everyone else," he told UK newspapers.
"We have goals and creativity all over the team. Obviously Phil added to that, there is no doubt about that.
"The fact is he has gone now and we have to think about what we have got that is going to get the job done. I have every faith in the boys that we just move on now.
"I don't think it should affect us at all."
Liverpool are fourth in the Premier League and three points off second-placed Manchester United, with Coutinho having played a key role in helping Klopp's side enjoy a strong season so far.
While he believes his team can cope without Coutinho, Oxlade-Chamberlain paid tribute to the Brazil attacker.
"I knew what a world class talent Phil is before I came here and in the short time I played with him I saw what an influential part he was of the side," he said.
"He was a big character around the place and a fan's favourite – rightfully so. He was an amazing player and he did great things for Liverpool.
"When you lose anyone like Phil, I wouldn't say you're losing out, but you want as many good players as you can have in your team. That's football, that's the business that we are in. People come, people go.
"Great players will leave clubs and clubs will bring in great players. You don't like to see friends leave – and Phil was a really good guy – but you wish them all the best."
The Reds face the toughest task in the league on Sunday, taking on leaders Manchester City at Anfield.