The Welshman secured a unanimous points victory over Ramirez, although his belt was not on the line after the Mexican failed to make the weight.
Warrington is Selby’s mandatory challenger after beating Dennis Ceylan in October, and Selby believes the fight would be good for British boxing. “First of all it’s a massive fight,” Selby said. “He has earned the mandatory position so to get there he has to be a good fighter.
“We’ve sort of exchanged words in the past but a fight between Josh and I would be massive and fantastic for British boxing.”
Selby, who lost his mother just days before he defended his title against Jonathan Victor Barros in July - a fight which had been postponed after the Argentine failed a blood test - appeared keen on putting on a good show.
Ramirez may have arrived in England eight pounds over the featherweight limit, but he, too, was up for the fight, and the southpaw provided a nagging test throughout the 12 rounds.
The Mexican came out full of intent in the opening exchanges but as the contest wore on, Selby, fighting in white shorts with gold trim, began to wear his opponent down.
Selby caught Ramirez with some good shots towards the end of the third before an upper cut in the closing moments of the fifth and a clean left in the ensuing round, ensured he was ahead on the scorecard when the fight reached its midway point.
Despite his endeavour, Ramirez, who until Saturday night had never been the distance, began to tire, but Selby failed to take meaningful advantage.
The Welshman appeared intent on ending the bout with a stoppage in the final round, but despite a slip from Ramirez, his opponent made it to the bell.
The judges scored the contest 118-110, 119-109, 116-112 in Selby’s favour as the Welshman successfully defended his title for a fourth time.