Saturday’s victory over Cardiff City moved the Lions six points and six places clear of the relegation zone, with only three games remaining.
Millwall’s survival hopes look much better after back-to-back victories, but Harris does not want anyone to relax until safety is guaranteed.
The Lions manager told NewsAtDen: “I always have to look at the worst-case situation because that’s my job.
“I told the players, ‘Well done for last week, excellent performance on Saturday to back up the vital win against Leicester, but we’re not mathematically there yet.'”
“We always have to assume the worse and keep pushing. So one thought process is to go to Sunderland this week to win a game of football, and then we’ll in a very good situation.”
Saturday’s meeting at the Stadium of Light provides Millwall the opportunity to halt their three-game losing streak away from home, and Harris is eager to replicate the form seen in SE16 up north.
He remarked, “Look at Southampton away, and even though it was backs-to-the-wall for 90 minutes, we found a way to win a game of football and looked quite comfortable doing so.
“We went to Blackburn and got a really excellent point in a game we should have won, but then we went on to lose three games in Yorkshire against Leeds, Rotherham, and Huddersfield, two of which we didn’t deserve.
“But we shot ourselves in the foot by losing the games rather than the opponent winning them. We have to get back to the habit of Southampton and Blackburn where we were the best version of us that we could be. So the demand from me to the players is can we now be a Millwall team that puts in a Den performance on the road.”
