Mourinho was left frustrated as he thinks some of his fringe players should be taking advantage of such games to retain their spot in the starting lineup.
Gareth Bale cancelled out Peter Michorl’s opener on the cusp of halftime before Heung-Min Son gave the visitors the lead eleven minutes after the interval.
LASK got their equalizer in 84 minutes through Johannes Eggestein but Spurs swiftly restored their lead from another penalty which was converted by Dele Alli.
The Austrian side snatched a last-gasp equalizer courtesy of Mamoudou Karamoko.
“Nothing new really. The fact that the Europa League group phase doesn't motivate some of the players, I knew it,” the Portuguese coach said.
"That some players are fundamental for us and I always need on the pitch in any circumstance, a couple of these players to give a little bit of balance to the team.
"As an example, (Pierre-Emile) Hojbjerg and Sonny, without them I don't think we would have a positive result. Nothing really that I learn. The players know and I share my feelings with them, I am normally right.
"When I saw the warm-up before the game I had a feeling and I told the players before the game that there was a huge difference in intensity, communication and enthusiasm in their warm-up and our warm-up because I was looking at both. Nothing surprises me."