The Blues have now lost eight of their 15 Premier League games following Saturday's 1-0 defeat to Bournemouth and sit 14th in the table, just two points clear of the relegation zone.
Nevertheless, Courtois - who returned to the starting XI against Bournemouth after missing 17 games through injury - hopes success in the Champions League could be the catalyst they need to boost their league form.
"I think we have been a bit unlucky some games this season, but we have the same good team as last year and that team won the league. So I think we have the quality to get out of this situation," Courtois told the official Chelsea website.
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"We have to regroup again and show strength against Porto in the Champions League and next Monday at Leicester."
Chelsea travel to Premier League leaders Leicester City after their match against Porto in midweek and Courtois is confident they can get a good result against Claudio Ranieri's men.
"Leicester away will be a difficult game. We knew last year it was not easy there and now they have the confidence and are playing really well," he added.
"It will be a very tough game, but we are confident we can push on there."