Andy Murray one win away from meeting with Jamie Murray
Andy Murray and his doubles partner Feliciano Lopez could play the Scot's brother Jamie in the quarter-finals at Cincinnati - if they win one more match.
Murray won their opening match against Horia Tecau and Jean-Julien Rojer 10-3 on a match tiebreak after splitting the opening two sets.
That set up a meeting with American pairing Ryan Harrison and Jack Sock in the round of 16, due to take place on Thursday.
Jamie Murray and his partner Neal Skupski, meanwhile, have won both of their opening matches, against Tennys Sandgren and Nicholas Monroe in the first round and Nicolas Mahut and Pierre-Hugues Herbert.
Though they are playing apart in Cincinnati, the Murray brothers have played plenty of doubles alongside each other, most recently in Washington DC, where they beat Edouard Roger-Vasselin and Mahut before falling to Michael Venus and Raven Klaasen.
In total, they have won two ATP doubles titles together, the most recent one coming in Tokyo in October 2011.