Retegui has taken his game to a new level since his August change from Genoa.
Gomez told L'Eco di Bergamo: "It's not a surprise to me. I already knew him when he was at Tigre, I knew he had everything it takes to do well. When he arrived in Bergamo I wrote to him: 'If you're intelligent and follow (coach Gian Piero) Gasperini, you'll score at least 20 goals'.
"He's proving to be a great striker".
Asked about comparisons with former La Dea star Duvan Zapata, he said: "Difficult, Duvan was devastating, the defenders were afraid of him. Retegui is different, but he has all the qualities to leave his mark."
On whether Ademola Lookman can be likened to him, Gomez also insisted: "He's not like me. He's hungry for goals, I was hungrier for assists. His ability to target the man throughout the game is impressive, he's grown a lot in team play, you can see that he talks to his teammates and integrates well into Gasperini's system."
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