The north London side produced a lethargic and lacklustre display against the Belgian outfit on Thursday (16 February), who rested a number of key players as they look to improve their league fortunes.
Pochettino says Tottenham did manage to create some clear opportunities and was disappointed that his side could not punish Gent in the second half.
The Argentine did not seem too deflated about the defeat, however, and believes the tie is very much "open" ahead of the second leg at Wembley Stadium.
"(It's) very frustrating, the tie is open now," said Pochettino after the match. "The first half was even, the second half we changed our formation to try and find a solution and we have some clear chances to score. I'm disappointed because we had opportunities to score before we concede, but the tie is open now.
"It wasn't a good performance but we need to understand that it's difficult to play in the Europa League. Now we need to fight from the beginning (in the second leg) and turn the result around."
Pochettino admitted his side's confidence took a knock after their loss at Anfield, but believes Tottenham can regain belief by proving that they can "play well and win" at Wembley next week.
"I think until the Liverpool game we were on a good run," Pochettino added. "It's true our confidence has dropped but today was a different competition. We tried to find a way to score but it wasn't our best game. It's a fantastic chance for us to make Wembley home and demonstrate that we can win there. It will be great to show ourselves that we can play well there ahead of next season."
Tottenham midfielder Eric Dier added that his side were erratic against Gent and, unlike his manager, thinks they did not create enough chances to beat the Buffalos.
The England international does however remain confident Spurs can turn things around when the two sides lock horns next week in the return leg, but conceded his side lacked quality at the Ghelamco Arena.
"We fought but we didn't create enough chances to win," Dier said. "It's a natural reaction, it's hard to stop when you go a goal down, you want to give everything. Maybe we were a bit erratic.
Asked whether Tottenham can turn the tie around in the second leg, Dier added: "Yeah, I don't see why not. It's difficult to come away to these European grounds and we were just lacking quality at times."