Samson was on 15 at the time when Brook grasped a simple opportunity at mid-on and the India opener went on to score 89 to set the platform for a huge total of 253-7.
England put in a huge effort in the reply but ultimately fell seven runs short to be eliminated at the last four stage.
"I'll hold my hands up and say that I made a big mistake there dropping Samson," Brook said on reflection after the game.
"Catches win matches, don't they? Unfortunately, it just didn't stay in my hands… Obviously, it's in the back of your mind.
"I kept on looking at the scoreboard and he was piling the runs on. I was like, 'I'm going to have to get 89 tonight'."
England head coach Brendon McCullum told Sky Sports: "I probably more look at their two catches that they took, to be honest.
"This is not an easy ground to field at, particularly when the crowd's as loud as what it is and the ball is sailing everywhere… Axar Patel being able to execute those catches, it was the difference between the game (being won or lost)."
India's Sanju Samson believes clarity in his role and position has given him the confidence to play the type of innings he did against England in the T20 World Cup semifinal.
The West Indies cricket team has been stranded in India for more than four days, prompting head coach Daren Sammy to express his frustration on social media on Thursday.
New Zealand seamer Matt Henry heaped praise on the Black Caps' bowling unit for their performance against South Africa in their T20 World Cup semifinal win on Wednesday.
The Proteas were blown away by New Zealand in their T20 World Cup semifinal clash, going down by eight wickets with more than seven overs to spare.
