It was Almagro’s second tournament win of the year and the 12th of his career.
Baker, 27, was playing in his first ATP final after being sidelined for almost six years having undergone five surgeries (three hip, one elbow, one hernia) before returning to tennis in July 2011 at the Pittsburgh Futures.
Baker should rise to around 140 in the world from his current 216.
“It was a great week. Every time you go onto court you want to win. I am a competitor, I hate losing,” said Baker.
“But it has been an unbelievable week. I hoped to qualify at the start of the week and win a match or two, before going to Roland Garros. Obviously, I did much better than that. I think even in the qualifying, I felt as if I was playing pretty well.
“I won my three matches easily and knew I was playing good tennis.”
Almagro added: “Baker lost the final today, but he is back, he is playing very good. I think if he plays as he did this week, then he will win many, many tournaments.”
The Spaniard is seeded 12th for Roland Garros, which starts on Sunday.
He opens against Italy’s Paolo Lorenzi.
Baker will play the French Open on a wildcard and takes on Belgium’s Xavier Malisse in the first round.