SUNDERLAND have scored twice in injury-time to rescue a point in two of their last four games – but Neil Harris has warned Millwall need to be on their guard for 90 minutes at The Den on Saturday.
The Black Cats came from 3-0 down to draw 3-3 with Bristol City on February 10, before Callum McManaman scored in the 96th minute for another 3-3 against Middlesbrough last weekend.
Millwall take an eight-game unbeaten league run into the contest after last Saturday's 1-0 win at Burton, their third successive victory.
"I think they will be a threat for 90 minutes because they've got some really good players," Harris said. "From our perspective we've found a way in a difficult February period to win games.
"You couldn't tell from watching it on TV or even standing on the sideline how difficult it was to play on that pitch last weekend. It was very bobbly, the conditions were windy, it was a tight pitch, little space for passing.
"But we found a way to get our noses in front and once we're in front we're difficult to peg back. I've got the likes of Tim Cahill and Jason Shackell to come on and give us that experience.
"And Fred Onyedinma again I thought was phenomenal, it's not just what he does with the ball, it's without the ball as well. He covers the ground so quickly.
"It's a great position for me as a manager to be in."
Sunderland played 4-2-3-1 when the sides drew 2-2 in November. But boss Chris Coleman has been setting up with three centre-backs lately.
Harris said: "At this level it's about adjusting constantly because teams are always changing tactics. Burton changed during the game to go 4-4-2 and as soon as they did we nullified it by going with five at the back.
"It's learning all the time, but shoring things up towards the end of games has worked for us this season. We've got a clean-sheet mentality.
Meanwhile, Chris Coleman is impressed with the job Harris has done with Millwall in almost three years in charge.
Coleman's Sunderland are without a win in six league games ahead of the clash.
"They're a tough team to play against, very well organised and they're not opposed to playing ugly if they need to. That's a feather in their cap," Coleman told Sunderland's official website.
"But they also play good football. Neil Harris is doing a really good job. It's his first job in management and, he's been there a few years and he's done fabulous, really, really good.
"Of course at home they are strong, it's never an easy place to go and they are on the back of three straight victories.
"But it doesn't matter for us, whether it's Millwall, Middlesbrough, Aston Villa, it's about us grabbing and being greedy and taking everything that we need to take.
"It' a bad run at a bad time for us, but bad runs come to an end."
Image: Millwall FC