Germany's entertaining but predictable Bundesliga was suddenly hit by two shocks last week to its two biggest clubs.

League leaders and defending champions Bayern Munich were defeated 3-1 by Portugal's Porto in their Champions League quarterfinal first-leg clash. However, their rivals Borussia Dortmund suffered an even bigger setback when their longtime coach Jurgen Klopp said he would quit the club in the summer.

Klopp's departure came as a bolt out of the blue, given he had ­repeatedly said he would not quit during the season, having signed a five-year extension in 2013. Klopp said he was no longer the best manager for Dortmund, having taken them as high as he could.

Outspoken and unconven­tional, Klopp, who often prowled the sidelines in a tracksuit rather than a suit, was considered a candidate for big clubs like Manchester United and ­Arsenal. Given that he said he would not be taking a break, there are growing expectations he might take the reins at Manchester City if Manuel Pellegrini is sacked.

Klopp's sudden decision to resign may have been sparked by Dortmund's struggles this season. Ravaged by injuries and the loss of star players, Dortmund had been languishing in the relegation spots in mid­season before a recent winning streak saw them climb to mid-table. Dortmund also crashed out of the Champions League after being beaten by Juventus in the second round. At times, Klopp looked haggard and emotionally spent during Dortmund's losses this season, when his side often ceded easy goals and failed to score frequently.

Whatever the future, it is the end of an incredible era for Dortmund. With Klopp as manager from 2008, the club won two Bundesliga titles, a ­German Cup, and reached the Champions League ­final in 2013. His brash and outspoken manner, notably exemplified by his impassioned berating of the fourth official in a 2013 Champions League game, made Klopp one of soccer's most notable characters. His on-field successes saw him become one of ­Europe's most capable and well-known managers.

If Klopp moves to a bigger club, there is a good chance he could repeat his success given he has already reached the highest levels with Dortmund. He has more than earned the right to leave on his own terms.

The author is an editor with the Global Times. hiltonyip@globaltimes.com.cn