Juventus were astonishingly held to a 3-3 home draw by Lech Poznan as the Europa League group stage kicked off on Thursday while holders Atletico Madrid began the defence of their crown with a 1-0 defeat at Aris Salonika.
Legia Warsaw's teenage defensive midfielder Krystian Bielik is to undergo a medical at Arsenal, the Polish club said on Thursday.
Italian teams Juventus and Sampdoria were knocked out of the Europa League on Wednesday and holders Atletico Madrid were staring at an early exit after a 3-2 home defeat by Greek side Aris.
Hooligans clashed with police and damaged the stadium after Legia Warsaw won the Polish Cup final 5-4 on penalties against Lech Poznan in Bydgoszcz on Tuesday.
Liverpool captain Steven Gerrard came off the bench to score a hat-trick in the last 15 minutes as the struggling Premier League side came from behind to beat Napoli 3-1 in the Europa League on Thursday.
Holders Atletico Madrid won for the first time in the Europa League this season, beating Rosenborg 3-0, while Emmanuel Adebayor scored a hat-trick as Manchester City beat Lech Poznan 3-1.
Former European champions Ajax Amsterdam and Celtic, who both suffered the indignity of being knocked of the Champions League qualifiers by underdogs this season, will meet in the Europa Leagueafter being drawn together in the group stage on Friday.
Ajax Amsterdam, returning to the stadium where they last won the Champions League 20 years ago, squandered a two-goal lead to draw 2-2 against 10-man Rapid Vienna on Wednesday.
Portugal, Denmark, Poland, Serbia, Austria, Croatia and Ukraine are among countries which will again be able to enjoy league football, albeit in unusual circumstances with no spectators allowed at games.
London sides Tottenham Hotspur and Arsenal made winning starts as did fellow Premier League club Leicester City.
CSKA Moscow must close part of their stadium for their next Champions League home game following the racist abuse hurled at ManchesterCity's Yaya Toure by the Russian club's fans last week, UEFA said on Wednesday.
Seven-time European champions AC Milan hit back from two goals down against Celtic to claim a 4-2 victory that sent them into the Europa League knockout phase on Thursday as they were among 14 teams to progress in Europe's second-tier competition.
Juergen Klopp got a taste of the problems at Liverpool as his first home game as manager ended in a frustrating 1-1 draw against Rubin Kazan who played more than 50 minutes with 10 men in the Europa League on Thursday.
Salzburg won the Austrian Cup with a ruthless 5-0 destruction of second tier Austria Lustenau in the final as the season resumed following the coronavirus stoppage on Friday.
New Liverpool boss Juergen Klopp made it three wins from his last three matches with a 1-0 success at Rubin Kazan in Russia that left them second in Group B, two points behind Swiss club Sion on Thursday.
The FIFA 2022 World Cup will kick-off in Qatar on Sunday, November 20. Here is a list of the 26-man squads playing in the quadrennial global football extravaganza.