With Benfica, he quickly became a fan favourite at the Estádio da Luz, being also referred to as a "force of nature" due to his powerful build, stamina and combativeness – he also scored regularly in big games, being the owner of a powerful long-range shot. Arguably his greatest moment with the Lisbon side came on 6 November 1991, in the last round prior to the group stage of the season's European Cup: against Arsenal, at Highbury Park, he assisted once and netted twice in a 3–1 win (4–2 aggregate success). Sporting coach Bobby Robson found him to be the most impressive player in the Portuguese league.[3][4]
However, Isaías would be left out of the Benfica squad in 1995 by coach Artur Jorge, who was proceeding to a team reshuffle that would result in the darkest period in the club's history – at that time, the veteran was still one of the squad's most influential players and top scorers.
Subsequently, Isaías moved to England with Coventry City for £500.000, signing a two-year contract and becoming the first Brazilian to ever play in the Premier League.[1][5] He featured in just 14 competitive matches for the Sky Blues over a period of two seasons, due to differences with manager Gordon Strachan and his refusal to cancel his contract after no compensation would be paid.[1] Isaías scored twice during his time for Coventry in games against Chelsea and Middlesbrough.[6]
^Malheiro, João (July 2006). Memorial Benfica 100 Glórias [Benfica Memorial, 100 glories] (in Portuguese) (Third ed.). QuidNovi. p. 74. ISBN978-972-8998-26-4.