The German suffered a knee injury back in June and, in his absence, Martinez rose to the occasion and played a key role in Arsenal winning a record 14th FA Cup.
It led to questions being asked about who would be Arsenal’s no1 this season, but in the end Martinez left to join Aston Villa in a £20million deal.
Arsenal’s decision appeared vindicated on Thursday night as Leno was named man of the match as the Gunners beat Liverpool on penalties in the fourth round of the Carabao Cup.
Leno kept a clean sheet during the 90 minutes and then saved two of Liverpool’s penalties to see his team through to the quarter-finals.
“I have never feared it (not being no1), because the club always gave me the feeling that I was the no1, I am the no1 and I will be the no1," said Leno.
“So that was always very good from the club. I think my job is to prove it every week and I think I have done it today again.”