Spurs were usurped at the top of Group C after Cenk Tosun's second-half effort saw the hosts eke out a 1-0 win at the Ataturk Olimpiyat Stadium.
It was a result which left head coach Pochettino understandably frustrated, while he was also unhappy with the disruptions to the game.
Less than eight minutes were on the clock when the floodlights first failed at Besiktas' temporary home, leading to the players being taken off the field and the suspension of play for nigh-on 17 minutes.
To compound matters, with victory all-but secured for the hosts, the power again failed in stoppage time, leading the team to having to once more leave the field before playing out the final few minutes.
"It is difficult to explain," Pochettino said of the power cuts
"We had a chat with the referee and you need to accept the situation.
"It's not possible [to change] nothing
It's frustrating if that happens..
it was laughable."
Pochettino rejected the notion the breaks could have negatively impact his players, although conceded it does little to improve the Europa League's standing.
"Maybe yes, it's not good for reputation of the competition," he said.
"Yes, it is always bad when you need to stop two times for the floodlights
If all the stadium switched off the lights, then maybe you would understand because something wrong has happened.
"But all the stadium was with light, except the pitch
But it is not an excuse, we need to look forward.
"We need to see the draw on Monday and to win the Europa League
It's a shame we didn't finish on the top of the table."
This was the second successive Europa League match in which Spurs had to overcome play being suspended.
Last month's clash with Partizan Belgrade was brought to a temporary halt after three separate individuals encroached onto the at White Hart Lane pitch, leading to UEFA handing down a 15,000 euros (£11,870) fine just hours before this match.
The main annoyance for Pochettino this time, though, was the result rather than the disruptions.
"We deserved more tonight, we created many chances," he said
"We didn't score and in football you need to score.
"I am disappointed with the result because I think we deserved more than this result.
"I am disappointed with result, I think like my players too
We created chance to score and always in football you need to score
"Tonight we are really disappointed because I think the team created chances and deserved more on the pitch."
Those sentiments were not shared by Besiktas counterpart Slaven Bilic at the end of a hard-fought encounter.
"It's a great win for us, a brilliant result," he said
"We were brave hearts tonight.
"I don't have to tell you how many players we were missing tonight
They were all players we use who were out.
"The players we missed, any club in world would miss them, so our win tonight was even bigger.
"The atmosphere was great, fans were great, really playing and fighting
We really wanted to beat them."
Source : PA
Source: PA