Jacobs said: "I'm disappointed because we would have liked to have won the game. But it was always going to be a tough one.
"If it were down to attitude, focus and how they have conducted themselves through the week we'd have won the game easily.
"But we knew that wouldn't be the case. That was only part of it. I said to the players before the game this is the day you can make your statement, this is the day you can have your say about yourself."
Jacobs added: "A real small positive is we got a clean sheet and Grimsby are no closer to us for people who see glasses as half empty."