The 30-year-old former Tottenham and Inter Milan playmaker collapsed during Denmark’s opening Euro 2020 match against Finland in June.
Eriksen was given a standing ovation by the crowd and both sets of players at the Brentford Community Stadium as he made his entrance early in the second half.
He has been fitted with a implantable cardioverter defibrillator, but was unable to continue his career with Italian champions Inter Milan, with ICDs not permitted in Serie A.
That paved the way for a January return to the Premier League, where he spent seven years with Tottenham between 2013 and 2020.
Brentford will be relying on Eriksen to find his old form as they slip closer to the relegation zone in their first season in the top flight since 1947.
Thomas Frank brought on his fellow Dane with the Bees losing 2-0 and down to 10 men after Josh Dasilva’s early red card.