Victory earned Newcastle a home tie against Glasgow Warriors on Saturday in the Round of 16, but director of rugby Richards was far from pleased with their performance.

Ultimately, though, Newcastle’s resilience paid off thanks to a 79th minute try from Cameron Nordli-Kelemeti.

Richards told the club website: “I think we were probably a little bit too complacent on the day, and took our foot off the gas beforehand.

“People might say Zebre haven’t won a game all season, but they’re playing against good sides – the likes of Leinster Rugby, Edinburgh Rugby and those boys.

“They’re all quality sides, and they’ve come on leaps and bounds in that company.

“We weren’t quick enough into the breakdown, weren’t physical and hard enough in the contact area and our kicking game lacked a bit of imagination.

“Zebre came out firing, and we probably didn’t pay them enough respect if we’re totally honest about it.

“Having said that, when you’re down and needing scores late on to win, we came back and did it, which is credit to the boys.”

Zebre, for whom fly half Antonio Rizzi was outstanding, led 9-0 and 22-13 at different points of the contest, but could not quite hold one.

Having praised their opponents, Richards said his players should have coped better with referee Ludovic Cayre’s interpretation of the breakdown.

Richards said: “I said before the game that adapting to a French referee was the most important thing tonight, and we couldn’t quite do it.

“Some of the penalties we gave away were a bit bizarre, but to some extent you’ve got to expect that in terms of interpretations of the law.

“We didn’t quite adapt to the way he was seeing things, and it cost us.

“But it was all about getting a home draw, and bringing Glasgow here will hopefully be a great occasion.

“We played them in pre-season, they’re a good side and I’m sure they’ll bring their support down over the border.

“It’s a big game between two good teams, and when you’re getting to the business end of European competitions there’s obviously plenty riding on it.”

Dean Richards admitted Newcastle Falcons were too complacent as they left it late to pip Zebre Parma 25-22 in the EPCR Challenge Cup.