Floyd Mayweather Jr has taken aim at Conor McGregor following the Irishman’s apparent retirement, saying he’ll be “waiting to punish” him should he return. McGregor made the <a href="https://www.thenational.ae/sport/other-sport/what-a-ride-it-s-been-ufc-superstar-conor-mcgregor-announces-retirement-1.1029939">shock announcement on social media</a> on Sunday that he was quitting combat sports - the third time he has retired in four years. The former two-division UFC world champion, who last fought in January, then told ESPN that “the game just does not excite me, and that’s it”. McGregor later posted a picture of a cake emblazoned “Happy Retirement Daddy”. However, Mayweather offered his thoughts early on Monday. The former five-division world champion boxer, 42, <a href="https://www.thenational.ae/sport/other-sport/floyd-mayweather-jr-beats-conor-mcgregor-with-a-10th-round-stoppage-to-take-his-record-to-50-0-1.623166">defeated McGregor in a money-spinning boxing bout</a> in August 2017 and then retired, with talk of a rematch - however unnecessary - never really being put to bed. Taking to Instagram after McGregor’s latest announcement, Mayweather said: “If I’m not mistaken, didn’t you tell Mike Tyson you could beat me if we fought a second time? "Now you’re quitting! I thought you wanted to beat the best? Well, if you decide to come back, I will be waiting to punish you again.” Many followers of mixed martial arts believe McGregor, 31, will be back in the octagon sometime soon. A former champion at both flyweight and lightweight, he is said to be frustrated by his recent inactivity. McGregor was expecting to fight this summer, but the coronavirus crisis disrupted his plans, while last week UFC president Dana White recommended the hugely popular fighter waits until September to return. McGregor has said he wants to take on either lightweight champion Khabib Nurmagomedov or interim belt-holder Justin Gaethje, although those two are first set for a unification bout. Speaking to ESPN, McGregor said: “The game just does not excite me, and that’s that. All this waiting around. There’s nothing happening. I’m going through opponent options, and there’s nothing really there at the minute. There’s nothing that’s exciting me. "They should have just kept the ball rolling. I mean, why are they pushing [Nurmagomedov-Gaethje] back to September? You know what's going to happen in September, something else is going to happen in September, and that's not going to happen. "I laid out a plan and a method that was the right move, the right methods to go with. And they always want to baulk at that and not make it happen or just drag it on. "Whatever I say, they want to go against it to show some kind of power. They should have just done the fight - me and Justin for the interim title - and just kept the ball rolling."