Tim Henman plays his second round-robin match at the Las Vegas Open on Thursday cautiously optimistic he is getting over his recent knee injury.
Henman beat Lopez in their only other previous meeting
Henman faces Spaniard Feliciano Lopez knowing victory will see him move into the quarter-finals.
After beating France's Nicolas Mahut 6-1 6-2 in his first outing since October earlier in the week, Henman revealed: "The knee seems to be fine.
"I still need to build my confidence in it but I'm excited to be out on court."
The 32-year-old appeared to be moving well in his first match, having also been hampered by a recent bout of flu which kept him out of the World Tournament in Rotterdam last week.
He added: "I am still a little bit cautious with the knee having been out for some time.
"But to be playing with no pain and moving much better is the most important thing."
Serve-volleyer Lopez edged past Mahut in his first group match after coming from a set down to claim a 3-6 6-3 7-6 victory.
However, the world No 96 will have little time to recover after nearly two hours on court, in contrast to Henman who will have had almost two days to rest.