Inter Milan midfielder Christian Eriksen scored his first goal for the club since last month's move from Tottenham Hotspur to set up a 2-0 win at Ludogorets Razgrad in their Europa League last 32, first leg on Thursday.
Getafe pulled off a surprise 2-0 home win over last year's Champions League semi-finalists Ajax Amsterdam, while Manchester United were held 1-1 at Club Brugge in wet and windy conditions.
Wolverhampton Wanderers' Diogo Jota scored a second successive hat-trick in the competition to lead his side to a 4-0 victory over Espanyol and Arsenal won 1-0 at Olympiakos Piraeus with a late Alexandre Lacazette goal.
Inter were frustrated for more than an hour by their Bulgarian opponents until Denmark playmaker Eriksen fired a low shot into the net from just outside the penalty area in the 71st minute.
"I think he can do much better than what we've seen today," said Inter coach Antonio Conte. "I'm happy because the goal always gives confidence, but he has to find the rhythm and intensity that have made him stand out in the past years."
Substitute Romelu Lukaku sealed Inter's win with a stoppage-time penalty, the Belgian striker's 22nd goal of the season, after Anicet Andrianantenaina was judged to have handled following a VAR review.
United were quickly in trouble in Belgium when Emmanuel Dennis lobbed the ball over Sergio Romero to give Brugge a 15th- minute lead, but Anthony Martial levelled in the 36th minute when he raced through to place a shot past Simon Mignolet.
United, with new midfield signing Bruno Fernandes on the bench, struggled to create many chances in the difficult conditions.
At Molineux, Jota opened his account in the first half for Wolves when he poked in from close range and fellow Portuguese Ruben Neves volleyed the second early in the second half.
Jota fired home the third from Matt Doherty's pass before completing his hat-trick with a strike from the edge of the box.
Pierre-Emerick Aubameyang and Bukayo Saka combined to set up an easy finish for Frenchman Lacazette to score the winner for Arsenal in the 81st minute and they nearly had a second when Sokritis Papastathopoulos headed against the woodwork.
Brazilian pair Deyverson and Kenedy scored in each half for Getafe against Ajax. Deyverson finished off a well-worked free kick to celebrate his European debut for the Liga club with a goal after 38 minutes and Kenedy broke clear to add a second in the last minute.
There was a remarkable comeback by Rangers who scored three goals in the last half hour, including a brace from Ianis Hagi, to beat Braga 3-2 after trailing 2-0 to the Portuguese visitors.
Daichi Kamada scored a hat-trick to help Eintracht Frankfurt to a 4-1 win over coach Adi Huetter's former club RB Salzburg.
Viktor Kovalenko grabbed the winner as Shakhtar Donetsk beat Benfica 2-1 and Sporting defeated Istanbul Basaksehir 3-1.
Youssef En-Nesyri equalised as Sevilla rescued a 1-1 draw at Cluj after Ciprian Deac put the Romanians ahead with a penalty.