Norwegian side Molde secured a thrilling 3-2 win over Legia Warsaw. Eirik Hestad opened the scoring in the 11th minute, and Kristian Eriksen doubled the lead shortly after.
Fredrik Gulbrandsen made it 3-0 just before halftime, latching onto a superb through ball from Emil Breivik.
However, Legia fought back with goals from Kacper Chodyna and Luquinhas in quick succession during the second half to stay in contention.
Meanwhile, Real Betis and Portuguese outfit Vitoria Guimaraes played out a dramatic 2-2 draw in Spain.
Following a goalless opening half, Cedric Bakambu put Betis ahead in the 48th minute, only for Joao Saraiva to equalize three minutes later.
Former Real Madrid midfielder Isco seemed to have sealed the win for the Andalusian club with a goal in the 75th minute, but Nelson Oliveira struck in the final 10 minutes to ensure Vitoria heads into the second leg on level terms.
With everything still to play for in the second-leg fixtures, these matchups promise even more excitement in the weeks ahead.
