Real Madrid and Maccabi Playtika Tel Aviv have deep rosters, which means that any number of players might step up during their playoff series. Fabien Causeur did that for Real in Game 1.
Causeur was Real's x-factor

After four consecutive losses, Real needed a good start against Maccabi, and Causeur provided it. Maccabi took an early 4-6 lead but Causeur hit a floater and a three-pointer, then found Guerschon Yabusele for an alley-oop dunk in a 9-0 run that put his team ahead, 13-6.
When Maccabi rallied and tied the game, 34-34, in the second quarter, Causeur decided he had seen enough. He buried a pair of three-pointers in another 9-0 run that put Real ahead for good, 43-34, near halftime. When Maccabi got closer again, late in the third quarter, Causeur followed a three-pointer with an up-and-under layup to restore a 63-54 margin.
When the dust settled, Real had beaten Maccabi 84-74 behind Causeur's 20 points, tied for the most in any Game 1, and 21 performance index rating, the second-best among all opening-game players. He was efficient wherever he shot, too, hitting 3 of 5 two-pointers, 4 of 6 threes and 2 of 2 free throws. Causeur added 4 rebounds, 5 assists and a steal before fouling out, leaving Real on the right track to win the game.
"I think our defense gave us opportunities to win the game," Causeur said afterward. "I think that the way Maccabi is playing defense, they helped a lot on [Walter] Tavares and [Vincent] Poirier, and that gave us opportunities to find open threes."