Despite beating Doncaster 2-0 at The Den, Neil Harris warned his Millwall team that he expects a higher level of performance than the one he witnessed on Tuesday evening.

After Steve Morison bagged a brace within eight minutes to provide the Lions with an immediate two-goal lead, the hosts were unable to push on and seal a more convincing victory.

And Harris was critical of his side’s inability to punish travelling Rovers.

“We weren’t very good at times,” the 38-year-old admitted.

“I’m delighted with the clean sheet and with Steve Morison’s two goals, but at 2-0 we should have gone on to score three, four or five.

“If you don’t kill teams off you always leave the back door open.

“We can be better than that tonight and we have been in every match in the last seven or eight games.

“It should have been game over after 15 minutes.”

The Lions boss felt Millwall took their foot of the gas after securing such a commanding lead and suggested the performance was a reality check following the huge result against Sheffield United.

Harris added: “I think we took our foot off the pedal after eight minutes if I’m being honest.

“We didn’t hit our standards that we’ve been setting in recent weeks.

“I didn’t like what I saw from my team from eight minutes to half-time and I told them that.

“If anyone was getting carried away after top performances against Sheffield United and Swindon then today was a reminder that if we don’t hit our standards, any team at this level can beat you.

“I think we were poor in general between both boxes, but we defended really well and I’m delighted for the team to keep a clean sheet.”

While Harris held mixed feelings on Millwall’s overall performance, he was full of praise for Morison.

The 32-year-old striker reacted quickly to take advantage of a defensive blunder after five minutes, before smashing home his second of the evening from a Shane Ferguson free-kick just minutes later.

“I thought he was outstanding again,” Harris said.

“He’s played even better than that and not had the goals so I’m pleased with him, but I’m disappointed that we’re not giving him the match ball.

“I thought he held the line well, he doesn’t stop and continuously gives us an outlet.

“He’s enjoying his football and playing very well for us.”