Bayer Leverkusen are heading back to the UEFA Champions League after a two-season absence, having gone from ninth when Peter Bosz took over in December to fourth on the final day of the 2018/19 campaign.
Leverkusen's emphatic win over Hertha Berlin on Matchday 34 – coupled with defeats for Borussia Mönchengladbach and Eintracht Frankfurt – ensured that Die Werkself will join champions Bayern Munich, Borussia Dortmund and RB Leipzig in next season's elite European competition.
It has been a remarkable turnaround under Bosz, who admitted he had "unfinished business" in the Bundesliga after an ill-fated spell in charge of Dortmund in 2017. The Dutchman has overseen 11 wins, one draw and five defeats during the Rückrunde, enabling Leverkusen to move into the top four for the first time all campaign thanks to their comfortable 5-1 victory in the German capital.
Having missed out on Champions League qualification by a whisker in 2017/18 – BVB pipped them to fourth place on goal difference – Leverkusen had a shaky start to the new season. Defeats at Gladbach, at home to Wolfsburg and away to Bayern put former boss Heiko Herrlich under immediate pressure, but two wins on the bounce seemed to have his side back on track.
On Matchday 6 Leverkusen were 2-0 up with an hour gone at home to Dortmund, but ended up losing 4-2. UEFA Europa League and DFB Cup commitments seemed to take their toll, though a 6-2 away win at Bremen and a 5-0 cup success at Gladbach in late October gave glimpses of what Kai Havertz, Julian Brandt and Co. could deliver when in full flow.
A run of two wins in eight league matches didn't help Herrlich's cause, however. He was eventually relieved of his duties in December, even though, by that stage, he had recovered to guide Leverkusen to the last 32 of the Europa League as well as enjoying a final streak of three wins in four Bundesliga games.
Bosz stepped in on 23 December, taking over with the 2002 Champions League finalists ninth in the table and seven points off the top four.
"The people in Germany haven't seen the real Peter Bosz yet,” he said on his arrival. “Now they'll get to know him at Bayer Leverkusen, but I can't repeat the mistakes that I made at Dortmund. I have to learn from that experience."
Watch: Bosz's Bundesliga reboot with Bayer
The former Feyenoord and Hansa Rostock midfielder swiftly abandoned the 4-2-3-1 formation preferred by Herrlich in favour of the Dutch-style 4-3-3 that he had employed with Ajax on their run to the Europa League final in 2016/17.
The change didn't bear fruit immediately, since Leverkusen lost their first game in 2019 - once again at the hands of Gladbach. But it soon allowed many attacking talents to flourish, with Julian Brandt, Kai Havertz, Kevin Volland, Leon Bailey, Lucas Alario, and Karim Bellarabi all on target as they scored 11 goals in their next three games. That spell included a 3-1 success over Bayern Munich on Matchday 20, with Bosz’s side the only one to get the better of the record champions in 2019.
February also saw Leverkusen bow out of the DFB Cup (away at Heidenheim) and the Europa League (on away goals against Krasnodar) but perhaps those setbacks were a blessing in disguise.
Only Dortmund beat Die Werkself in the league between the end of January and mid-March, as a run of six wins in seven put the five-time Bundesliga runners-up right back in the hunt for a European place.
Leverkusen were sixth by that stage, four points off the Champions League places with nine games to go. But three straight defeats against Werder Bremen, Hoffenheim, and Leipzig – in which they conceded 11 goals – threatened to derail Bosz’s European ambitions entirely.
After the 4-2 loss at Leipzig, they were back down to ninth. With only six games to go, Leverkusen were 10 points behind Frankfurt, who occupied fourth spot.
The Eagles were on a thrilling ride to the Europa League semi-finals, however, and their heroic efforts in that competition ultimately drained them. Eintracht took two points from a possible 18 to finish the league, while Leverkusen rediscovered their form to collect 16 points between Matchdays 29 and 34.
With three games to go, a 6-1 thrashing of a tiring Eintracht certainly helped – Leverkusen blitzing their rivals with a new club record six first-half goals. And despite being held by Schalke on the penultimate day, Bosz watched his side steal into the final Champions League spot after running riot at the Olympiastadion.
Watch: Leverkusen romped to a record-breaking win over Frankfurt on Matchday 32
"I'm proud of the team," Bosz said after the win over Hertha. "After the most important Matchday of the season – the last one – we are in fourth place. We have achieved something special by qualifying for the Champions League. We worked really hard for it."
That they did so is testament to Bosz's influence. Havertz – the Bundesliga's Player of the Month for April – finished as the club's top scorer with 17 league goals, scoring 11 of them after the new manager took over. The 19-year-old thus became the first teenager in Bundesliga history to net that many in a single campaign.
Volland was also a beneficiary of the 55-year-old's arrival, with eight of the forward's 14 goals and eight of his nine assists coming in the second half of the season.
Six of Brandt's seven strikes and eight of the Germany midfielder's 11 assists also came after the winter break, while Argentine attacker Alario finished with five goals in the last three games – including a hat-trick against Hertha.
Watch: Kai Havertz, Europe's best young midfielder
Overall, after scoring 26 goals and conceding 29 in the first half of the campaign, Leverkusen netted 43 and let in only 23 in 2019. Only Bayern (42) and Leipzig (35) picked up more points than Bosz's side (34) in the second half of the season.
"We had nothing more to lose," sporting director Rudi Völler said of Leverkusen’s resurgence under Bosz. "No one believed that we could be fourth anymore."
Next season people will write Leverkusen off at their peril. Hoffenheim’s Germany midfielder Kerem Demirbay has already signed up for 2019/20, and – with Bosz and Völler now able to offer Champions League football – Die Werkself could well be a force to be reckoned with.