But the powerful American, this year after posting several lackluster results, has dropped to a singles ranking of 15.
Roddick scored two breaks of serve to lead 4-0 in the first set. Then at 5-2, ace number five struck down the tee set up set point. A netted Lu backhand return ended the set after 31 minutes of play.
In the second set, a Lu backhand down the line passing shot winner at 2-1 breakpoint sent the qualifier ahead 3-1.
Lu would hold at love after connecting with an ace out wide to lead 4-1 before closing out the set 6-3.
After complaining several times to the chair umpire that Luís grunt could be heard late after the ball was struck
which made it sound like a call from a line judge, Roddick held on to break serve to lead in the final set 3-1 before finishing the set 6-2.
In the second round Tuesday, Roddick is set to meet the unseeded, 72nd ranked Grigor Dimitrov of Bulgaria. The two
players have never before met on the ATP Tour.
In 2004 in Davis Cup competition, Roddick struck the fastest serve ever at 155 miles per hour.
Roddick could face the top seeded Rafael Nadal of Spain in the semifinals over the weekend. This week in the USA, the
Tennis Channel is offering daily televised live matches from Shanghai.