Mardy Fish had to come through a tough test from Frank Dancevic to book his place in round three of the Sony Ericsson Open in Miami, Florida.
Both players gave little away in the first set, but world number eight Fish found a decisive service break at 4-3 before he served out the set 6-3.
Dancevic battled hard in the second and the Canadian had his opponent on the back foot when he broke Fish's first service game.
Fish soon broke back, and the competitors held their serves to take proceedings into a tie break.
The American went into overdrive in the tie break as he exploited Dancevic to take three mini breaks on the way to a 7-1 win.
