[5][6] In the early days of Salvador Lutteroth's Empresa Mexicana de Lucha Libre (EMLL) the shows usually featured Americans in the main events with most of the Mexican wrestlers working lower on the cards.

[7] Segura's popularity kept growing, making him one of the first Mexican established Main Events, getting top billing all over Mexico.

[9] Due to incomplete records of results for that time period it is not clear exactly when Octavio Gaona regained the championship.

[8][11] By 1943 Segura had become involved in another long running, very intense rivalry, this time with Enmascarado Rojo ("The Red Masked Man").

On the first show in the new building Firpo Segura took on his rival Gorila Macías in the semi-main event, no results document the actual outcome of the match.

[13] At some point in 1943 Segura became a two-time Mexican National Heavyweight Champion as he defeated Rey Duran to regain the championship.

[11] On March 28, 1944, Firpo Segura won yet another mask as he defeated El Chimpancé in a Lucha de Apuestas match in Guadalajara, Jalisco, forcing his opponent to unmask.

[14] In later 1945 he became involved in a feud with the masked "Grey Shadow" who wanted a match for the Mexican National Heavyweight Championship.

The feud between the two led to a Lucha de Apuestas match on March 22, 19 where Segura defeated his opponent, forcing Grey Shadow to unmask and reveal that his name was Daniel Aldana.

[11] The following year longtime rival Daniel Aldana, now using his own name after unmasking, gained a measure of revenge on Segura as he won the Mexican National Heavyweight Championship from him.