GELSENKIRCHEN -- Borussia Dortmund midfielder Marco Reus said his team "simply botched it" in a bitter derby loss to Schalke 04 on Sunday.
Reus, 28, told Sky after the game: "We wanted to win this game today because we could have leapfrogged Schalke. We simply botched it."
Yevhen Konoplyanka broke the deadlock after 50 minutes in the Veltins Arena after Daniel Caligiuri had won the ball off team captain Marcel Schmelzer in the build-up to the goal.
Schalke centre-back Naldo doubled the lead for the final 2-0 scoreline in the 82nd minute with a powerful free kick from distance to open a four-point gap over their Ruhr rivals. BVB drop back to fourth place.
Although both goals were scored after the break, Reus criticised his team's first-half performance, saying: "We did not play any good football and failed to make spaces tight for our opponents. We let them play. We did not do well there at all."
Meanwhile, team captain Marcel Schmelzer apologised for his mistake in the 50th minute that ultimately brought Dortmund on the path to defeat, telling reporters: "It was a deserved loss. We managed to drag a 0-0 into half-time and came highly motivated out of the locker room.
"It was very bitter that I made the mistake that led to the opening goal in this game of all games.
"I want to apologise to everyone who sympathises with the Black and Yellows. I'm also very sorry for the team. We only managed to create chances after we adjusted our tactic but then it was already too late."
The left-back explained that it was Dortmund's plan to trigger Schalke's pressing by moving the ball to their full-backs. But he conceded that the idea turned out to be counterproductive.
"We knew that Schalke's wing-backs would charge our full-backs very energetically on both sides," he said. "It was our plan to take advantage of the spaces in behind.
"But either we didn't make the right runs into that space or when the runs were there, we failed to deliver the passes. Overall, nothing really worked out for us today."
Asked why BVB could not replicate last week's performance in which they managed to dismantle VfB Stuttgart 3-0, Schmelzer said: "The 3-0 against Stuttgart may have left a false impression as the first half wasn't a nice game either.
"I don't think that we will be able to turn it around for the remainder of the season. Today's game was very important for us and to lose it deservedly makes the situation worse. It was the most important game of the year and we lost it. It's really hard to point out exactly."
Dortmund maintain a four-point gap over fifth-placed Leipzig in the fight for the Champions League spots but their European ambitions may have taken another hit as Chelsea loanee Michy Batshuayi rolled his left ankle in a challenge with Benjamin Stambouli in stoppage time.
The forward left the stadium on crutches with a bandage around his left calf. He was brought to a hospital after the game for further examination, a club official told ESPN FC.