Gomez, Lukas Podolski and Thomas Muller were all omitted from the starting line-up in the 4-2 win over the Greeks and replaced by Andre Schurrle, Marco Reus and Miroslav Klose, with the latter two getting on the scoresheet.
"Naturally it hurt me to do that [drop Gomez]" Low told DFB.de. "Mario scored three goals and was involved in another. Podolski too scored a goal last game but the time was right to make changes.
"It worked out well in the end. Reus played well, so did Schurrle and Klose. That was the key to the win."
Low also had praise for Sami Khedira and Mesut Ozil, who both played significant roles in the victory, with the former scoring Germany's second goal.
"He [Khedira] was very dynamic, very present. He has really become a leading figure in our side since 2010. He leaves his position to put pressure on the opponent but then he falls back in again. It is difficult to beat him in a tackle and that is good for those who play around him," he added.
"[Ozil] totally deserved to be man of the match. He was always involved, always wanted the ball and moved a lot. Practically everything went through him."
Low was pleased to see his team reach their fourth consecutive semi-final at a major tournament, saying: "It's a great accomplishment. After [Euro] 2004 no-one thought the team would go on to win 15 consecutive competitive matches.
"It is also the youngest team of the tournament which puts things into perspective. They deserve credit for what they have done.
|14/1||Mario Gomez is 14/1 to be named Uefa's player of the tournament at Euro 2012 with Paddy Power|
"We can all be proud of the team. No question about it, we were the deserved winners. We missed a few opportunities at the beginning and lost the ball a bit too easily but we played well from the beginning and did not let the goal disrupt us."
When asked who he would rather face in the next game, England or Italy, Low noted the similarities between the two nations, and said either would offer a tough test.
"Both teams are very difficult. Roy Hodgson has turned England around. They are very tight and not divided in two like they were in 2010," he said.
"He has given the team a clear order and vision. They are better organised and are quick on the counterattack. Italy play quite similarly."