Diego Simeone claims Atletico Madrid have benefited from their transfer ban as it has allowed the club to focus on developing their current stars.
FIFA imposed the ban on Atletico for breaching the rules over the transfer of foreign players under the age of 18, meaning they could not sign anyone in either of the 2017 transfer windows.
"We have turned a negative situation into a positive one," he said. "Not being able to sign has made us focus on making the players that we have even stronger: Thomas, Luciano [Vietto], Lucas [Hernandez], [Angel] Correa.
"That has given us the chance to compete well. There is more competition for places now."
Atletico are set to bring in Diego Costa when the ban is lifted in January, having agreed a deal with Chelsea, and Simeone is delighted to see the forward return.
"The arrival of Diego makes us very happy," he added. "That a player of his status wants to come to Atletico Madrid.
"There are still steps to make it official, steps that do not depend on us."
The win against Sevilla was Atletico's second game at their new Wanda Metropolitano and Simeone paid tribute to the fans for creating an intimidating atmosphere.
"As people adapt more to the stadium, the atmosphere is going to be fantastic," he said.
"Did you see when people shouted? It was incredible. I was below and it looked like a Roman circus. Truthfully, it thrills me. I am excited."