Long regarded as merely a backup for Miroslav Klose and an underperformer at the big tournaments, the 26-year-old grabbed his chance at the first opportunity to strengthen his claims to be Germany's first choice striker in the tournament.
Gomez, a surprise starter on Saturday with Klose on the bench, was in the right place at the right time, as he has done so often for his club Bayern Munich in the Bundesliga and the Champions League this season, to head in the only goal on 72 minutes.
Until then the Germans had found their attacks stymied by a gutsy and clever Portuguese defence.
Gomez himself was shut out and frustrated by Portugal central defenders Pepe and Bruno Alves, and was about to be taken off for Klose when he nodded in Sami Khedira's cross.
Had he not scored German media would be awash with stories about his failure to rise again to the occasion. It was a similar case at Euro 2008 where his claim to fame was a spectacular miss against Austria.
At the 2010 World Cup he was also upstaged by Thomas Muller, who was the tournament's top scorer.
Now, however, he can expect to be the first choice after Low opted to start with him instead of Klose, who is only five goals away from Germany's all-time goal scoring record of 68.
Gomez took his tally to 23 international goals but none of the other 22 will have done so much for his reputation as a lethal finisher than the one on Saturday.
While he may not have been as effective in the past for the national team, he has become irreplaceable for Bayern, netting 12 goals in the Champions League and another 26 in the Bundesliga this season.
He helped them reach the Champions League final and converted a penalty in the final shootout against Chelsea when other big name players like Bastian Schweinsteiger and Arjen Robben failed to do so.
A year earlier he was crowned the Bundesliga top scorer.
"I've had two successful years behind me," a beaming Gomez said. "I'm very very happy... I had a good feeling from the start here and I wanted to give something back for the trust [the coach put on me]."
He can expect to hold on to his starting spot now as long as he keeps scoring.
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