2016 proved to be a breakthrough year for Elias. After winning an ATP Challenger Tour tournament in Turin by defeating Enrique López-Pérez in three sets and earning position in the top 100, being ranked no. 94, Elias continued capitalizing on his Challenger Tour success as he won his sixth Challenger title in Mestre, Italy by defeating Horacio Zeballos in straight sets. In July 2016, Elias made his first splash on ATP World Tour tournament level in Bastad, Sweden after defeating Christian Lindell, Taro Daniel, and pulling an upset against compatriot João Sousa on his way to his first ATP World Tour semifinal. However, in the semifinals, Elias lost to Fernando Verdasco. Later in July 2016, Elias participated in another ATP World Tour tournament in Umag, Croatia. Elias defeated Guillermo Garcia-Lopezin the round of 32 and then pulled one of the biggest upsets of the tournament by defeating top seeded Pablo Cuevas in a close encounter. That win marked Elias' first win over a top-20 player. Elias then defeated Pablo Carreño Busta and reached his second consecutive ATP World Tour semifinal, where he lost to Fabio Fognini in straight sets.
Playing style
Gastão Elias is offensive baseliner who puts focus on hitting hard and accurate groundstrokes to push his opponents and hitting winners, however also making comparable to winners amount of unforced errors. His serve and forehand shot are dangerous weapons, which are the main instruments in winning points, but return game is one of the weaknesses, which can be exploited by the best players whose game heavily based on strong serve and volley tactic. While feeling most comfortable at the baseline Elias makes occasional runs to the net, though these runs can't be classified as the key aspect of his game. Although his favourite surface is hard, most of his success came on clay.