The World Cup winners edged to their victory thanks to an 89th-minute goal from Toni Kroos at the Estadio de Balaidos.
Low said it was the ideal way to finish 2014, a year which saw Germany win the World Cup for a fourth time.
"I don't think you can ask for a better end to the year than that," he said.
As for his team's performance, Low said there were plenty of areas for his side to work on.
"I was very pleased in the second half with the attacking play. We had better action than in the first," he said.
"We must continue to develop and improve in some things further. That was a very good start today."
Low was most pleased with his defence, who stood up in the absence of Mats Hummels and Jerome Boateng.
"I think we tried to play with order and attacked calmly. Spain always combine their play well, so we had to put another man in midfield," he said.
"Furthermore we lacked Hummels and Boateng and Spain always have fast wingers who join up with the attack.
"I'm happy to say that our defence had an exceptional game."
Kroos' 30-yard strike found the bottom corner to give Germany their victory, and the Real Madrid star said it had been a dream finish to 2014.
"These two recent wins are just what we'd hoped for," Kroos said.
"It's been a great year and it's a great way to end it."