Borussia Dortmund CEO Hans-Joachim Watzke says he flirted with pulling the club out of the Champions League after Tuesday's team bus attack before resolving not to give in to the bombers.

Atletico Madrid coach Diego Simeone believes his side face a "pure night" of football when they take a 1-0 to Leicester City's King Power for the second leg of their Champions League quarterfinal.

Three bombs hidden in a hedge that exploded when the Borussia Dortmund Champions League team passed by proved that no sporting event is now safe from a militant attack, experts said.

They lost the game, but realised there is more to life than soccer.

Security has been tightened around the star-studded Real Madrid squad, led by superstar Cristiano Ronaldo, for Wednesday's Champions League match at Bayern Munich following the Dortmund team bus blast.

At least one person has been injured by an explosion on the bus taking the Borussia Dortmund soccer team to their Champions League quarter-final first-leg match against Monaco on Tuesday, the German club said.

Atletico Madrid have grown accustomed to slaying Europe's giants in the Champions League under Diego Simeone, but ending Leicester City's run may prove even tougher than ousting Barcelona or Bayern Munich, according to Filipe Luis.

Juventus coach Massimiliano Allegri believes that defending is just as much as an art form as attacking and advises anyone who wants to watch a show to go to the circus.

Bayern Munich are sweating on the fitness of Mats Hummels for Wednesday's Champions League home clash against Real Madrid after the Germany defender injured his ankle in training on Sunday.

Barcelona were pitted against Italian champions Juventus in the Champions League quarter-final draw made on Friday to set up a repeat of the 2015 final which the Spanish side won 3-1.

Atletico Madrid booked their place in the Champions League quarterfinals for a fourth consecutive season but had goalkeeper Jan Oblak to thank for avoiding defeat in a 0-0 draw with Bayer Leverkusen on Wednesday.

Tiemoue Bakayoko's superb header fired Monaco into the Champions League quarter-finals as Wednesday's 3-1 victory condemned Pep Guardiola's Manchester City to a painful exit on away goals.

Monaco owe most of their recent success to their young guns, but when they face Manchester City looking to overturn a two-goal deficit in their Champions League last-16 tie on Wednesday, they will turn to a more experienced player in Radamel Falcao.

A stunning late strike by Keita Balde helped Lazio to a 3-1 win over Torino on Monday that keeps the capital side in the hunt for Champions League qualification in Serie A.

Paris St Germain started their recovery from an embarrassing Champions League exit in Barcelona with a 2-1 win at bottom club Lorient to maintain their Ligue 1 title challenge on Sunday.

Barcelona's amazing 6-1 victory over Paris St Germain on Wednesday that sent them through to the Champions League quarter-finals will forever stay in the memories of supporters, coach Luis Enrique said.

Jose Mourinho takes his Manchester United side back to former club Chelsea on Monday with a place in the FA Cup semi-finals at Wembley up for grabs and a score to settle with his old employers.

For an hour Arsenal were at least salvaging some pride against Bayern Munich, then the ceiling came crashing down as they exited the Champions League last 16 on Tuesday with a matching pair of 5-1 defeats against the merciless Bundesliga giants.

Arsenal manager Arsene Wenger, whose contract expires at the end of the season, will make a decision about his future based on the "bigger picture" and not a recent slump in form.

Arsenal will have to produce the biggest second leg comeback in a Champions League knockout tie to avoid a seventh successive exit at the last 16 stage when they host Bayern Munich on Tuesday.