Bayer Leverkusen welcome Borussia Dortmund on Sunday with the hosts sitting clear atop the Bundesliga table, having dropped just two of a possible 36 points to start the season.

Although only two points ahead of a Harry Kane-powered Bayern Munich, Leverkusen are already a whopping ten points in front of Dortmund, with only 12 matches played. 

While many have credited manager Xabi Alonso for giving Leverkusen's long-suffering fans hope of adding to a sparse trophy cabinet, a shrewd summer recruitment drive has also set them up for success. 

Using the proceeds of Moussa Diaby's sale to Aston Villa, Leverkusen brought in striker Victor Boniface, winger Jonas Hofmann, midfielder Granit Xhaka, while Alex Grimaldo joined from Benfica on a free. 

Alonso hailed the summer additions' "football intelligence", telling AFP and other media in an interview "we knew they were going to have an almost instant influence on our game".

"We have signed very strategic players to give us stability... to be more efficient and consistent. That gives you the possibility to be more regular in the Bundesliga."

Since the transfer window closed, German media has reported that each of the quartet were rejected by Dortmund in the summer -- other than Hofmann, who had two previous stints at Signal Iduna Park. 

Criticism has grown, particularly with Dortmund's new additions Felix Nmecha, Marcel Sabitzer and Ramy Bensebaini showing indifferent form and failing to fill the gap left by budding superstar Jude Bellingham. 

The architect of Leverkusen's summer transfer window, sporting director Simon Rolfes, had his contract extended to 2028 on Tuesday, a reflection of the former player's efforts. 

Rolfes, who played 377 times for Leverkusen, said his side had "gained enormous quality" and was proud to have extended at "a demanding, modern club hungry for success."

Leverkusen's brightest star, Germany midfield maestro Florian Wirtz, was rested for Thursday's Europa League trip to Swedish side BK Hacken -- a reflection of Sunday's importance to the league leaders. 

There is more at stake for Dortmund than just losing touch with the league leaders. 

Alongside RB Leipzig, who have won the past two German Cups, Dortmund have been the team most likely to break the champions' dominance -- likely making Leverkusen's stunning emergence as 'Bayern hunters' even more of an issue for the visitors on Sunday. 

"This is the most difficult task in Germany at the moment," said Dortmund defender Mats Hummels on Tuesday regarding the trip to Leverkusen. 

"We need to stand our ground."

One to watch: Serhou Guirassy (Stuttgart)

Stuttgart striker Serhou Guirassy is set to make his first start since October, returning from a hamstring injury at home against Werder Bremen on Saturday. 

The 27-year-old has 15 goals in ten matches, scoring at an incredible strike rate of one goal per 46 minutes this season. 

The injury did not stop Guirassy's stunning form however, with the France-born Guinea forward coming off the bench to score the winning penalty against Dortmund earlier in November. 

In his absence, Brighton loanee Deniz Undav has stepped up, scoring six goals in his past six matches. 

Stuttgart manager Sebastian Hoeness confirmed on Thursday "they will both be in the starting XI against Bremen. I'm looking forward to the double-pronged attack".  

Key stats

Zero from eight: Union Berlin have never beaten Bayern but have drawn three of eight -- all with a 1-1 scoreline.

18: Harry Kane has 18 goals from 12 league games this season.

Nine of 17: Denmark striker Jonas Wind has scored nine of Wolfsburg's 17 goals this season, more than half. 

Fixtures (1430 GMT unless stated)

Friday

Darmstadt v Cologne (1930)

Saturday

Bochum v Wolfsburg, RB Leipzig v Heidenheim, Bayern Munich v Union Berlin, Borussia Moenchengladbach v Hoffenheim, Stuttgart v Werder Bremen (1730)

Sunday

Mainz v Freiburg, Bayer Leverkusen v Borussia Dortmund (1630), Augsburg v Eintracht Frankfurt (1830)