City's 2-1 victory over Aston Villa in midweek left it third on the Premier League table, but it trails leader Liverpool by 18 points having played a game more.

On Monday (AEST), meanwhile, it faces Nottingham Forest at Wembley as it attempt to reach a third consecutive FA Cup final.

Having also been knocked out of the UEFA Champions League by Real Madrid in the Round of 32, the FA Cup is City's last hope of ending a below-par season with any domestic silverware at all. But even if that happens, Gundogan will not call it a success.

"The past has shown that it's not the standard we set for ourselves," Gündogan said.

"We know things were not good enough from our side throughout the season. We can't change that, we can only take it and be honest with ourselves. It's important to admit to yourself.

"There are two targets left for us. One is obviously to qualify for the Champions League next year, which is vital for the club and also for us players as well.

"The other one is to try to get to the FA Cup final. We're going back to Wembley for the semifinal and it's always special.

"It's going to be tough but it's going to be the only chance, with the Club World Cup, for silverware this season. We'll try to go for it."

City's title defence capitulated during a run in November and December in which a victory at home to Nottingham Forest was its only one in 13 matches.

With Forest winning the reverse 1-0 in March, Gundogan knows it cannot afford a repeat of that on Monday (AEST).

"The standard in the Premier League is so high," he said.

"If you go through all the teams, there is no league in the world that has this kind of standard. Every game is so tough. The FA Cup is a reflection of that and that's why these teams are there. Every team is so uncomfortable to play against.

"When we lost at their place we were not up to our game and that's what I mean. It gets punished in the Premier League. Maybe in the past we could have been at 70, 80 or 90 per cent and still win games but now it's so demanding. What they do, they do really well.

"They could be in the Champions League next season and they have a lot of quality. We know when we lost against them that it was just not good enough from our side. We have to do it better if we want to get into the final."