They are the first winners of multiple major men's doubles titles in a season since Bob and Mike Bryan won three in 2013.
The Australian Open champions were joined by French Open champions Marc Lopez and [no relation] Feliciano Lopez, who would play against fellow Spaniards, the unseeded Guillermo Garcia-Lopez and Pablo Carreno Busta, in the other semi. The duo only teamed up late previous year.
Murray and Soares had each lost in the Flushing Meadows final with a different partner - Murray a year ago with Australian John Peers, and Soares in 2013 with Austrian Alexander Peya.
Andy Murray, the Olympic gold medalist in Rio this year, lost in the U.S. Open singles quarter-finals to Kei Nishikori of Japan.
JAMIE MURRAY succeeded where his brother Andy failed by reaching the final of the US Open.
He joked: "I'm starting to move out of his shadow a little bit".
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"These tournaments are the hardest to win", said Murray, who also won the Wimbledon mixed doubles title in 2007.
An interception volley at the net by the British Davis Cup victor earned an early break in the second set and, with Soares dictating matters from the back of the court, they left little for Carreno Busta and Garcia-Lopez to attack.
Their 6-2 6-3 victory also means Jamie ends the year one grand slam title up on his younger brother, who was crowned champion at Wimbledon but lost in the quarter-finals in NY to Kei Nishikori.
"If I kind of come in and start saying, you know, I think you need to serve there or, hit your return there, they are not used to hearing that". "That's a complete lie", Jamie shot back, smiling.
After Soares had sealed victory in Arthur Ashe Stadium with a crisp forehand volley, Murray and his partner embraced in celebration before holding their arms aloft.
"I felt like Bruno was the guy that was going to help me achieve what I wanted to achieve on the doubles court", said Jamie. "The steak is on Jamie".
