Nam and his partner, India's Sumit Nagal, beat Japanese pair Yusuke Takahashi and Jumpei Yamasaki 6-2, 6-3 in the quarter-finals yesterday.
It's the first time Nam has made a semi-final at a Grand Slam. He is also the first Vietnamese athlete to do it.
In the next round, Nam/Nagal will play No 5 seed Miomir Kecmanovic (Serbia) and Casper Ruud (Norway) who won over William Blumberg/ Tim Paul from the US.
