Mariner said: "We have to try and look at the positives. The reaction was excellent from the players after going 3-0 down in 48 minutes. I knew we'd fight back because that's what we do but the first half just wasn't good enough.
"We were a different team in the second half. We scored three goals away from home but we got beat. It's pretty obvious what we need to tighten up on."
Mariner was full of praise for young striker Joe Mason after he notched his first senior goal in the 4-3 defeat at Sheffield United.
Mariner has predicted a bright future for the 18-year-old, who scored following his half-time introduction at Bramall Lane.
Mariner added: "Joe Mason is an incredible talent. He's going to be a very good player. He has a goalscoring instinct, his first touch is fantastic, he has pace and is brave."
Source: Team Talk
Source: Team Talk