The William Hill Scottish Cup defeat by Aberdeen at Parkhead on Saturday and their League Cup reverse to Morton are Celtic's only domestic losses this season.
Neil Lennon's men have won 13 consecutive Scottish Premiership games ahead of Sunday's visit of St Johnstone and have kept a club record 11 successive clean sheets in the league.
And Matthews is determined to finish the league campaign unbeaten to atone for their cup despair.
"We are obviously disappointed," Matthews said of their 2-1 loss to the Dons.
"We weren't happy with the way we played, we know we can play much better.
"But it's important we put that behind us and concentrate on keeping our run going in the league. I think it's got more influence on our season now.
"Obviously we are out of both cups, which is very disappointing for us, especially the Scottish Cup as we won it last year and wanted to retain it.
"So I think it's very important to keep our run in the league going."
The Wales international added: "We know it's going to get tougher every week because everyone is going to want to defeat us and break our run.
"So we have to be on top of our game. We can't have a performance like we did against Aberdeen."
Meanwhile, January signing Holmbert Fridjonsson was forced off with a foot knock during Celtic Under-20s 1-0 win over Kilmarnock on Tuesday afternoon.