Promising Spanish forward Martinez was signed from Valencia at the weekend and the 18-year-old arrives in East London with a fearsome goalscoring record.
Compared to Atletico Madrid star Fernando Torres, Martinez has notched more than 100 times over the past four seasons for Valencia's youth sides.
Spanish prodigy compared to Torres
The Spain U17 international has joined Slaven Bilic's revolution on a three-year contract and comes with some pedigree having helped Spain win the 2015 UEFA European Championship title.
Although Martinez's contract at West Ham does not officially start until July, Valencia have allowed the young star to move to England sooner to settled into a new country and surroundings.
And the ground, as well as the welcome he has received, has left him suitably impressed.
"Really happy to have seen the historical Boleyn Ground," Martinez posted on social networking site Twitter.
"I'm without words for all the messages of welcome!
"Thanks to all the West Ham supporters for the welcome messages."
Martinez's Olympic ambitions
West Ham fans are rightly proud of their history and fortress Upton Park.
And it has been just that this season with the win over Watford last time out securing a new top flight club record 15 games unbeaten at home.
Martinez will not get to play at the Boleyn, but he will no doubt have his eyes on forcing his way into Bilic's plans to play at the 60,000 seater Olympic Stadium in the near future.