Valencia defender Gaya popped up for the late leveler to deny Germany all three points in Stuttgart, after Timo Werner had given the hosts a 51st minute lead.
Elsewhere in the opening Nations League matches in Group D A4, Ukraine defeated Switzerland 2-1 in Lviv, with Premier League pair Andriy Yarmolenko and Oleksandr Zinchenko on the scoresheet.
The matches marked the return of international football for the first time since the coronavirus outbreak in March.
The Germans were undermanned with boss Joachim Low opting not to call up his Bayern Munich contingent after their UEFA Champions League run.
On the other hand, Spain boss Luis Enrique was taking charge for the first time in his second stint at the helm. He fielded Spain’s two youngest ever international in 17-year-old Barcelona winger Ansu Fati.
In League B, Russia got past Serbia 3-1 in Moscow with Artem Dzyuba scoring a double while Hungary shocked Turkey 1-0 in Sivas in Group 3.
Wales claimed a 1-0 victory away to Finland thanks to Kieffer Moore’s 80th minute strike in Group 4.
Shane Duffy netted a 90th minute equaliser to earn the Republic of Ireland a 1-1 draw in Bulgaria.
On Friday, Italy hosts Bosnia-Herzegovina in Florence while the Netherlands entertains Poland in Amsterdam.
On Saturday, England is away to Iceland, Denmark welcomes Belgium, 2016 European champions Portugal hosts 2018 World Cup finalists Croatia and world champions France go to Sweden.