Barca already boast a 16-point advantage over champions Real Madrid in La Liga, while closest challengers Atletico Madrid are six points worse off after playing a game more.
Valverde believes that his side are now the envy of teams not just in Spain but around the world, telling reporters: "I'm very happy with the players who I had before the arrival of these two players, and with the ones I had at the end of the summer and with the ones I have now.
"I thought Barca was the best team when I was the coach of Athletic and now I can see that. Barca is the best team in the world. "
Coutinho will not make his Barca debut until February due to injury, while Valverde hinted that Mina will also be left out against Real Sociedad on Sunday evening.