Borussia Dortmund coach Jurgen Klopp has said he fully expects Robert Lewandowski to join Bayern Munich when his contract expires next summer.

Lewandowski has been strongly linked with a move to Bayern for some time, with Jupp Heynckes having claimed after the Champions League final that the Poland striker “will not have to wait too long” to follow Mario Gotze to the Allianz Arena.

Dortmund, frustrated by Bayern’s pursuit of their key players and their failure to register an official bid, have insisted there is no possibility that Lewandowski will be allowed to join the European champions this summer.

However, there appears to be no prospect that the 24-year-old will extend his deal at the Westfalenstadion, and Klopp accepts his player is destined to make the switch on a free transfer in a year’s time.

“I think it is a fact that Robert Lewandowski will join Bayern at the end of the coming season,” he told Welt am Sonntag. “What matters now is what we do before that point. That is our concern, and we have an obligation to our fans to ensure we are competitive in the coming season.

“To a point, we were willing to discuss Robert’s desire to move, but since nothing happened during that period, we eventually had to say: ‘So now it no longer works for us’. And now we want to prove we can be successful in the coming year with a quality player like Robert.

“It is all about our results in the coming season, and I know Robert sees things the same way.”

As a result, Klopp is encouraging the supporters to maintain their support of Lewandowski during his final campaign.

“I have great confidence in our fans, but I also know that such issues are put to the test when things are working out,” he said. “If we lose a game because Robert misses a shot, you have to stay cool and show that you understand the big picture.”

Klopp remains hugely disappointed by Gotze’s decision to depart for Bayern, and the nature of the move.

Bayern opted to pay the Germany international’s buy-out clause and the deal was leaked to the media ahead of Dortmund’s Champions League semi-final with Real Madrid, and Klopp had vented his frustration at the timing.

Dortmund also released a statement revealing Bayern had not made contact over the deal, and Klopp said the whole affair was a “bigger disappointment” than the Champions League final defeat at Wembley.

“Until mid-April, Mario had been a part of our plans, and suddenly we were confronted with the reality that he wasn’t,” he said. “That was pretty tough.

“Basically, it is normal for a football club to want to sign a player from another team – we do that, too – but it was the date the transfer came out, the day before our important game against Real Madrid, that was offensive. Other than that, there wasn’t much about last season I found painful.”

Klopp has not given up hope that his side can get the better of Bayern this season, a side he felt were “last season quite possibly the best team in the world”, despite the champions’ financial might.

“We can’t just buy two players for every position like Bayern, and that is not something we can address exclusively with money,” he said. “We also want to continue to give very young players the chance to fill the gap.”

He added: “We have a bow and arrow and, if we aim accurately, we can hit the target. Only the Bavarians have, I feel, a bazooka. The probability that they will hit the target is so much better. Nonetheless, Robin Hood is said to have been very successful.”

Manchester United, Manchester City, Chelsea and Arsenal were also vying for Lewandowski’s signature.