Borussia Dortmund coach Thomas Tuchel has hailed the importance of Marco Reus in the wake of Saturday's hard-fought 1-1 Bundesliga draw with Cologne.
The Germany international netted a stoppage-time equaliser to salvage a point, having previously done the same in the 2-2 Champions League draw with Real Madrid in midweek.
Reus missed the opening stages of the 2016-17 campaign due to injury, but Tuchel has acknowledged the attacker has quickly made himself indispensable again.
"Reus is irreplaceable for us," Tuchel said at a news conference.
"This match was more proof of that."
Dortmund struggled to cope with Cologne's defensive approach after an impressive outing versus Madrid in Europe and Tuchel believes the busy calendar is one of the main reasons for their lack of consistency.
"There are a lot of reasons for our inconsistency," he added.
"One of the main reasons is that we are learning in matches rather than on the training pitch. We need time on the training pitch.
"But at least we are making progress.
"We had to put in a lot of effort and in the end it was worth one point. We will have to accept that and move on."