Floyd Mayweather carried out a very specific plan in his fight against Conor McGregor, and a lot of people are confusing that with McGregor "winning" or "dominating" a few rounds early on.
The consistent strategy of Floyd Mayweather is to feel out his opponent for the first few rounds, taking into consideration all of the factors he will need to be 100% concise with his decisions during later rounds, and in the process he might look as if he's getting beaten. The punches, which McGregor did throw, were off-target and missed more than they hit. That was deliberate.
Colin Cowherd explained why Floyd Mayweather's strategy saw him dominate the entire fight: