Youngsters Josh Onomah, Tom Carroll and Ryan Mason were all present in the initial XI, which prompted suggestions that Pochettino may have rued his decision as his side slumped to a 3-0 defeat at Westfalenstadion in the Round of 16 first leg.
But Pochettino denied those claims, indicating it was merely a poor performance by his team which he felt contained enough quality to beat Thomas Tuchel's Dortmund side.
"No regrets," Pochettino said.
"I'm very disappointed with the result but we didn't have a very good day. It was a bad day in the office.
"When we analysed the squad and picked the starting XI, we tried to win the game. It started OK but it was a really bad day for us."