Rovers appeared to be turning the corner after a dismal start to the season following morale-boosting victories over Arsenal and Leyton Orient.
But they suffered a setback at St James' Park as the Magpies ran out 3-1 winners to push Blackburn back into the bottom three.
While Steve Kean felt after the match that Rovers might have come back had the referee disallowed Newcastle's third goal for what he thought was a foul on Scott Dann, Samba has admitted there were few positives to take.
The defender believes Blackburn need to raise their level considerably at both ends of the pitch if they are to compete in the Premier League.
"That was not a good Blackburn team that turned up. It was not a good performance," he said in The Sun.
"The team is much better than we showed. We could've gone out and made it more difficult for them, we conceded soft goals and should've been tougher at the back.
"We must have more will and heart. Everything we can improve, every department.
"The team needs to fix things ourselves and make sure we stick together. We need to be more ruthless in both boxes because we've been beaten in both boxes.
"You need to push your luck and force your own destiny. We need to do that, we need to create more chances and push forward more."