Selby has three tournament wins in the last three months and looked capable of adding the Hainan Island event to his UK Championship, Munich Open and Masters successes after knocking in five half-centuries over five frames against the 14-year-old sensation.
‘The Jester from Leicester’ hit an opening-frame 52 followed by 69 in the third to go 3-0 ahead, before a 73 reply to Lu’s fourth-frame opening gambit of 64 made it a clean sweep heading into intermission.
And the Englishman finished the demolition job with another 73 in frame five to clear up having started with a run to 57.
Up next for Selby is fellow countryman Barry Hawkins, who was almost as emphatic in seeing off his own wild card qualifier, Ian Burns, by a score of 5-1 to begin his tournament campaign.
The big-breaking Dartford player responded to dropping the opening frame by taking the lead with knocks of 60 and 93 before taking the fourth on the final colour trail for a two-frame cushion at the break.
His momentum was not hindered by 15 minutes away from the table, building a 112 century break for 4-1 before clinching a place in round two in a tense and competitive sixth frame.
And Ding Junhui also progressed in the day's opening session after scraping a 5-4 victory over Michael Holt.
Ding hit tallies of 76 and 95 to go 2-0 up but was pegged back to parity at the mid-session interval.
World number eight Ding went back ahead at 3-2 and 4-3, the latter with a 65 in response to Holt's sixth-frame 54 - only for the Englishman to make the break of the match with a run to 99 which forced a decider.
But after a lengthy battle of safeties began the all important final frame, Ding was able to assume control of the table and break to 50, which was enough to secure a round-of-16 tie with either Mark Williams or Marco Fu.
Haikou World Open results – Wednesday session one
Mark Selby 5-0 Lu Haotian
Barry Hawkins 5-1 Ian Burns
Ding Junhui 5-4 Michael Holt