Asian heavyweights Australia and South Korea took big steps towards next year's London Olympics with emphatic qualifying wins on Sunday.
Australia sparkled to a 3-0 victory over trouble-hit Yemen, while South Korea were also well on their way to the third and final round after overcoming a dogged Jordan 3-1 in Seoul.
The Asian zone's top teams are all in action for the two-legged ties on Sunday and Thursday, with the winners split into three groups of four teams for final qualifying.
In seaside Gosford, striker Jason Hoffman scored twice and midfielder Mitch Nichols got the other to hand Australia a comfortable buffer to take into the second leg in Newcastle.
Hoffman headed home a Sebastian Ryall cross in the 14th minute, as Australia had nine attempts on goal before Yemen's first shot was saved by goalkeeper Andrew Redmayne on the half-hour.
Australia continued to press in the second half before Nichols added their second goal in the 67th minute with a close-range shot after a cross from the ever-present Hoffman, who rounded off the scoring in stoppage time.
"It could have been more to be honest. We missed some really easy chances and their goalkeeper made some outstanding saves as well," said team coach Aurelio Vidmar.
"We're pleased with that and now we'll hopefully go to Newcastle and finish it off."
Thursday's return match has been moved from Yemen to Australia due to security concerns in the Middle Eastern country following mass protests and unrest against the ruling regime.
South Korea were made to work harder for their win and had to come from a goal down after Jordan's Mahmoud Saleem Mahmoud Za'tara opened the scoring in first-half injury time.
But Kim Tae-Hwan equalised 11 minutes into the second half before midfielder Yoon Bit-Garam calmly converted a penalty with 13 minutes to go. Substitute Kim Dong-Sub put it beyond the visitors with an 86th-minute header.
Japan, China and North Korea all have home fixtures ahead of Iraq's mouth-watering clash with arch-rivals Iran later.
This week's 12 winning teams will be split into three groups of four for final qualifying, with the three top sides all gaining automatic entry to the Olympics.
The second-placed teams will play a three-way round robin with the winner going into a play-off with a side from the African confederation.
Men's football is played as an under-23 tournament at the Olympics, although the rules allow for three over-age players.