The Belgian admits it was an off-night for the visitors, who remain in third-place on the Premier League table.
“Yeah, it's a really big disappointment, I think,” said Lammens afterwards “We knew it was going to be difficult today, especially away here and the manager warned us.
“I think, in the first half, we weren’t at our best but then, heading into half-time, with a pretty good feeling after scoring that goal in the last minute. Against 10 men, we had a pretty good feeling.
“But he warned us it was not going to be easy, we had to attack them and try to break them quickly or the longer we had to wait for that, and the longer it stays 1-1, one opportunity and it can be changed.
“Today, that's what happened and it's nowhere near good enough, today, in every aspect. We have to learn from that.”