Had Chelsea come away with all three points, then they would have qualified for the next phase following Rosenborg's victory over Valencia in Spain.
But Grant declared: "We wanted to win but it was not easy to play Schalke at home. They needed to win because a draw was not good enough. It was not a bad result but not our best game.
"After so many good games in a short time we can have one game that is not in the high level. It is also an away game against a team who feel very good playing at home."
Grant added: "The Champions League is not the league it is another competition. You need to fight for the result and it is not easy to play away from home.
"We are in first place and everything is in our hands and I am very happy and confident about that. But we need to continue our job because it will not be easy.
"I don't think we defended so bad. It was not a bad game. It was not our best performance but not a bad game for us."