Andre Villas-Boas paid tribute to Gent's discipline after watching his Zenit side slip to a 2-1 defeat in Belgium on Wednesday.
Zenit went to the Ghelamco Arena in search of a sixth win from six Champions League Group H outings but were put to the sword by goals from Laurent Depoitre and Danijel Milicevic, as Gent became the first Belgian side to progress into the last 16 of the competition since Anderlecht in 2000-01.
While his team briefly restored parity through Artem Dzubya's 65th-minute strike following Depoitre's opener, Villas-Boas saw Milicevic earn the hosts a deserved victory 13 minutes from time and afterwards he credited their workmanlike performance.
"They played well organized and showed confidence through this group stage," said the Russian outfit's head coach.
"Their system is difficult to play. I think they deserved to go through."
The former Chelsea and Tottenham boss was frustrated by the display of referee and fellow Portuguese, Manuel De Sousa, however.
"I'm ashamed in his place," he said. "Seven yellow cards - it really was not needed in a match like this.
"He even gave us a card for a duel in midfield where no attack broke down there."
