A Saul Niguez goal proved enough for Atletico Madrid to win 1-0 over PSV, while Arkadiusz Milik netted twice to help Napoli come from behind and record a 2-1 win against Dynamo Kiev in UEFA Champions League action on Wednesday (AEST).
At PSV's Philips Stadium, Saul's persistence paid off in the 43rd minute, when the Spain international found the net with a left-footed shot after his initial effort with his right had been blocked.
However, last season's beaten finalists were indebted to Jan Oblak's first-half penalty save, as he turned away Andres Guardado's effort, for securing all three points from an absorbing Group D clash.
PSV also had a goal dubiously ruled out for a foul as their six-match unbeaten run in all competitions come to an end against the team that knocked them out of the same competition on penalties in the last 16 last term.
Meanwhile, at NSK Olimpiyskiy in Kiev, Milik scored his first goal of the game when he cancelled out Denys Garmash's opener following a fine cross from Faouzi Ghoulam, before netting his and Napoli's second shortly before the break with another header.
Kiev pushed hard for an equaliser in the second half, but they lacked the individual quality to really worry Napoli and their task became all but impossible when Serhiy Sydorchuk received his second yellow card for diving, the Serie A side holding on to their lead without any real problems.
In Portugal, it looked as though Benfica, quarter-finalists last season, would get their Group B campaign off to a winning start against Besiktas after they took the lead thanks to Franco Cervi's 12th-minute goal.
But Anderson Talisca, who joined Besiktas on loan from Benfica just last month, came back to haunt his parent club by netting a stunning stoppage-time free-kick to earn his new side a 1-1 draw.
It was the same scoreline in Switzerland, where Renato Steffen struck an 80th-minute equaliser for Basel as they drew 1-1 with Ludogorets in Group A.
Jonathan Cafu's breakaway goal just before half-time had looked set to secure a first Champions League group stage away win for the Bulgarians before the home side's late pressure eventually told.