However, Europe was to prove a more successful venture as the club's runners-up finish of 1977–78 qualified them for the UEFA Cup.

Lienen played in the final, and in each of the previous rounds, scoring two goals along the way (against Manchester City and future club MSV Duisburg).

This time, he was not to capture the prize as the team frustratingly lost on away goals to countrymen Eintracht Frankfurt.

Here, he and the team achieved a string of top-four finishes but fell short of collecting a league title medal.

In Summer 1987, Lienen left Borussia Mönchengladbach to set up a union for professional footballers in Duisburg, along with Benno Möhlmann and Frank Pagelsdorf.

Lienen remained at MSV Duisburg after ending his playing days, coaching the club's amateurs from 1 July 1989 to 22 March 1993.

[3] He quickly got the opportunity to move up into the first team management on 22 March 1993,[3] after the club regained its Bundesliga status.

[5] He then accepted the invitation of his former Borussia Mönchengladbach coach Jupp Heynckes to join him at Spanish club CD Tenerife as his assistant.

When Heynckes left Tenerife to move to Real Madrid C.F., Lienen's time in Spain was up and he returned to his homeland as head coach of Hansa Rostock.

[6] The next season proved a far trickier affair as the club sat in the relegation zone throughout the majority of the campaign.

[15] His spell back in the Canary Islands was less successful as before as the team failed to mount a promotion challenge.

[19] After a six-month absence from the Bundesliga, Lienen was recruited by Hannover 96 on 8 March 2004 after their dismissal of Ralf Rangnick.

The next season began poorly though, and hopes of building on the previous campaign's strong outcome evaporated.

[22] Lienen again looked abroad for his next position, and headed for a new challenge in the Greek Super League with Panionios for the 2006–07 season.

The following season was equally successful for the club, again finishing in fifth position, only to lose their UEFA Cup berth on the following playoff.

Panionios cited various disagreements from the start of the season, as well as the tension developing between players and staff, as the reasons for this decision.

[28] Lienen and 1860 Munich agreed to mutually terminate his contract on 17 June 2010 so he could make the move to Olympiakos.

[32] On 8 November 2010 he was named the successor of Christian Ziege at Arminia Bielefeld,[33] Lienen decided not to be manager of the club if they are relegated.

On 18 April 2011, Arminia announced that Markus von Ahlen would replace Lienen starting in the 2011–12 season.

[39] On 6 November 2013, Lienen was appointed as the new manager of Romanian Liga I club Oțelul Galați on a two-year contract.