Everton completed a deal to sign the 20-year-old midfielder from Lille earlier this week for a fee worth €40m.
As many as five clubs were interested in snapping him up, but the race ultimately came down to Everton and West Ham for his signature.
West Ham were the first club to match Lille’s asking price for him and the Hammers’ pursuit of the midfielder further convinced Everton to try and get Onana.
Senior officials at Everton are aware of Moyes’ eye for a signing and the convincing it takes for him to sanction a move for any player.
The West Ham manager’s decision to push for the midfielder’s signing further reinforced Everton’s belief in Onana’s talent.
Frank Lampard had several conversations with the midfielder and played a key role in helping Everton beat West Ham to his signature.
Former Everton striker Romelu Lukaku also gave a glowing reference of his time at Goodison Park to Onana.
