Sunderland, who were beaten 4-3 at home by Chelsea on Wednesday, have won just twice in the Premier League all season and sit bottom of the table.
However, Dossena was buoyed by the performance against Jose Mourinho's men and is confident he and his team-mates can pick up points when facing sides of lesser quality.
The defender believes Saturday's opponents Tottenham fall into that category.
"(Eden) Hazard had a fantastic game and you don't come up against players like him or (Juan) Mata every week," said Dossena.
"We know Chelsea are a great team. I know Tottenham are good, but I don't think they're as good as Chelsea.
"We have to show the same heart and same character because it's a very important game."
Even a victory over Tottenham would not pull Sunderland out of the drop zone, although three points could lift the club to 18th if results go their way.
"We've got another chance on Saturday to close the gap on the teams in front of us," added Dossena.
"We kept going (on Wednesday) because the mentality here is perfect. The fans are behind us and we want to win for them. At the end of the day, we didn't get them any points, but the mentality here is strong."
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