Julian Nagelsmann expressed his desire to see Robert Lewandowski receive a warm welcome on his Bayern Munich return, as he backed the striker to continue his fine start to life at Barcelona.

Lewandowski, who scored 238 Bundesliga goals during an eight-year spell with the Bavarian giants before heading to Camp Nou in July, has made a scintillating start to his Barcelona career. 

The Poland international has scored six goals in his first five outings in LaLiga, and turned on the style with a hat-trick in Barca's 5-1 Champions League thrashing of Viktoria Plzen last week.

Lewandowski will make a swift return to Munich with his new club for Tuesday's huge Champions League fixture, and despite the less-than-amicable nature of his departure, Nagelsmann believes he should be received warmly.

"If I see him before [the game] then I'm certainly going to give him my hand. I'm not sure if I'll see him beforehand, usually I don't," Nagelsmann said.

"I'm looking forward to our fans welcoming him back. When a player has been so strong for the team over the years, I think it's important. 

"He was an important part of the Bayern family. We had a personal exchange a couple of weeks back, not regarding football. I am looking forward to seeing him again."

Asked about Lewandowski's start to life in Spain, Nagelsmann added: "I think he can still continue to play at that level for a couple of years, I'm not sure how many goals he can score this season, I'm no genie. 

"I think it will be plenty. He has scored 40 plus usually, so I think he can do that in the Spanish league as well.

"I'm not sure if he's the most dangerous, but he's certainly one of their most dangerous players, the one that can score the most goals. They have great solutions there.

"Lewandowski always has great runs and positions inside the box. He's the most dangerous in front of goal, but if he doesn't get a lot of balls, it's difficult [for him]."

Having coached Lewandowski when he brought up a half-century of goals in all competitions last term, Nagelsmann is acutely aware of his talents, and believes Dayot Upamecano's past experiences of facing him could aid Bayern. 

"I have plenty of positions that I'm already pretty clear on," Nagelsmann added. "Upamecano has memories of playing against Lewandowski, back when he was at RB Leipzig. He knows him from our practice as well."

While Upamecano is set to start at the Allianz Arena, Leon Goretzka will not, as Nagelsmann looks to ease the midfielder in following his injury lay-off.

"The position next to Joshua [Kimmich] is going to be [Marcel] Sabitzer," Nagelsmann said. 

"I've had a chat with Leon, it was my decision to keep him on [against Stuttgart on Saturday]. We decided to keep him on for 94 minutes, that was a long time for him after the injury. He reacted well to it and is feeling good. 

"Him having to play from the start is not going to happen, we need him for the whole season and don't want to give him too many minutes at the start."

Meanwhile, Barcelona have suffered eight Champions League defeats to Bayern – twice as many as they have lost against any other opponent (4 vs Milan, Chelsea and Paris Saint-Germain).

Bayern also boast a 100 per cent record against the Blaugrana in the group stages and beat them twice in the competition last term, but Nagelsmann is keen to draw a line under those past meetings.

"We know Barcelona. They have a completely new mindset. You can delete the last few games against Barca from your memory, it's a whole different team, very aggressive," he said. "It reminds us of when Xavi still used to play himself. 

"In Gavi and Pedri they have great number eights that have great pressing actions as well. There's a great development there for the team, Xavi did a few things really well in the last weeks and months.

"They want to attack in a new way, and they're going to be very difficult opponents tomorrow."