First-half efforts from Irvine and Velupillay at a near-sold out 80,000-seat Olympic Sports Centre Stadium in Hangzhou on Tuesday continued Tony Popovic's unbeaten start to life as national team coach.
Not since Terry Venables in the 1990s has an Australian coach avoided defeat through their first six games, but that will mean nothing if Popovic does not navigate what is shaping as a pivotal June window.
The win over China has meant Australia, (13 points, +7 goal difference) retains the second automatic qualification spot in Group C.
But Saudi Arabia (10 points, -2 goal difference) are within touching distance after they held the already-qualified Japanese to a 0-0 draw in Saitama on Tuesday.
Australia host Japan in Perth on June 5 in the first game of the window while the Saudis face a short away trip to neighbours Bahrain.
The Socceroos then head to Saudi Arabia on June 11 for the final game of qualifying in a potential winner-takes-all encounter.
Goal difference decides which side will finish higher with the third and fourth-placed teams facing another round of qualifying for next year's tournament in North America.
Australia's away trip to face Saudi Arabia could be a dogfight but the Chinese - needing a win to revitalise their own hopes of automatic qualification - were bordering on passive for the opening 45 minutes on Tuesday.
Australia, on the other hand, began with purpose and nearly took a fifth-minute lead when a Brandon Borrello cross put Martin Boyle through on goal but the Hibernian man could only lash his shot into the Chinese side netting.
At the time it seemed like a wasted opportunity but China were second best to everything and it didn't take long for the Socceroos to make them pay.
After a Lewis Miller cross found its way to the edge of the China box, both Huang Zhengyu and Li Lei were both unable to dispossess a dogged and determined Irvine.
As he moved past the Chinese duo, St Pauli midfielder Irvine dispatched a dipping left-footed effort past Wang Dalei to give Australia a 16th minute lead.
More joy was to come from the Australia right wing when Miller, after combining with clubmate Boyle, fired in a low cross in the 28th minute.
China's defence was too concerned with energetic Socceroos striker Borello running towards the front post that they left Velupillay unmarked on the penalty spot.
As the ball deflected his way, Melbourne Victory winger Velupillay powered a downward shot towards the Chinese goal.
Unable to gather the skidding ball clearly, Chinese No.1 Wang could only watch as Velupillay's shot trickled past him and over his goalline.
It wasn't until the second half that the hosts really threatened the Australian goal but both times Maty Ryan, whose shutout was just the second clean sheet of the Popovic era, was up to the test.
Ryan gathered a Li effort with ease and palmed away a shot from recently-naturalised Brazilian-born playmaker Serginho.
Defender Milos Degenek had Australia's best chance of the second half but fired his shot into the side netting after being left unmarked at a corner.
