Gomez scored a fine header as Low's side opened the Group B campaign with a 1-0 success in Lviv, joining Denmark at the top of the 'Group of Death' after the Danes' shock 1-0 triumph over Holland.
Lazio frontman Klose - scorer of 14 World Cup goals - has been struggling with a thigh injury in the build-up to the tournament, meaning Gomez got the nod up front. Low said: "I spoke with Miro. He still needs maybe a few per cent at this moment. He hasn't played for quite while in the preparation."
He added: "They both trained really well but Gomez has been playing for the whole season, scoring lots of goals. He's a different type of player than Miro and he showed he has lots of different qualities - one chance, one goal."
Portugal coach Paulo Bento felt his side did everything well - apart from putting the ball in the net.
"Of course, I'm sad about the result," he said. "It was a very complicated game - we knew that before. I think the first 45 minutes we were stronger. Germany dominated a bit [in the second half]. They had more possession. They controlled game but we still defended well. In the later stages we did everything we could to create chances - we just didn't score."
Their hopes now rest on Wednesday's clash with Morten Olsen's buoyant Denmark.
"We have to do everything to recover now," Bento added. "We don't know what condition the Denmark players will be in now.
"Denmark is in more a comfortable position than we are - we can't get away from that - but we will try our very best. We will concentrate on the second game.
"It was always our goal to advance and we must be loyal to our will to win, to show great effort and we will try everything to succeed against Denmark."