Their victory ended the Bryans' six-year streak of finishing the year in top spot.
"This year we left it wide open. Tecau and Rojer got us. Deservedly so, they played well in the slams, won the Wimbledon title," Bob Bryan said.
"Usually what we say is to be number one you've got to win a slam. Credit to them, they did."
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
Wimbledon champions Rojer and Tecau will face Rohan Bopanna and Florin Mergea in Sunday's final at the O2 Arena.
"It feels pretty darn good right about now," Rojer said.
"There was so much riding on this match for us. We put in a lot of hard work, like many of the other teams do, of course.
"To have it come down to one match to play for the year-end number one spot, it's just a dream scenario."
(Reporting by Martyn Herman; Editing by Ken Ferris)
