Birmingham striker Marlon King says his side can take confidence from their 3-1 defeat to Braga in the Europa League on Thursday.
King scored his first goal for the St Andrews club after making the summer move from Coventry.
His goal brought Birmingham back into the game to make it 2-1, but they conceded late on to lose in their first fixture of the group stages to last year's finalists.
The Blues are also combining their European schedule with a busy Championship calendar and play Southampton this Sunday.
Chris Hughton's side have found it difficult to acclimatise to the second tier following their relegation from the Premier League last season - they are 12th after seven games
English top-flight clubs also involved in the Europa League, including Tottenham, Stoke and Fulham, have played as many as four fewer domestic games than Birmingham.
But King is optimistic about their chances in all competitions this season.
He said: "It was due to our own downfall with some of the goals if we look back.
"They were sloppy goals. But we can't be too down about it because we've got another tough game on Sunday.
"We had chances and you've got to take confidence from that, it wasn't a one-sided game. They didn't come here and outplay us.
"We know the quality they have but, as I said, we played a big part in their goals.
"We've got nothing to fear. This is the stage we want to be on. Everybody's saying there's lots of games but as a footballer you want to test yourself against the teams who have played in the Champions League and the top leagues. All the boys are enjoying it."