As on Friday, Scotland faced Israel behind closed doors at the Bozsik Arena in Budapest because of the political situation in the Middle East.
Scotland made the breakthrough 60 seconds earlier this time, with midfielder Weir shuffling across the edge of the penalty box before curling her drive into the far corner past goalkeeper Fortuna Rubin.
Only 16 minutes gone and all was looking good, but news came through almost immediately that Inter Milan forward Tessa Wullaert had also opened the scoring for Belgium - as we were.
The lead was extended eight minutes before the break as centre-half Clark headed home Kathleen McGovern's fine cross to the back post.
Again Belgium responded, Union Berlin defender Amber Tysiak with their second in Luxembourg on the stroke of half-time, but there were still no panic buttons being pressed.
However, alarm bells were ringing 11 minutes into the second half as poor marking by Clark allowed former Glasgow City team-mate Kats, the midfielder now of Mainz, to lash a shot into the top corner.
Goals from Inter Milan midfielder Marie Detruyer and Tysiak suddenly brought Belgium within one goal of the Scots and the nerves were jangling.
They seemed to be settled again thanks to a touch of fortune when Israel defender Asia Dercksen was harshly ruled to have handled during a goalmouth scramble and Weir coolly slotted home the penalty kick.
Any doubts seemed to be extinguished just short of the 80th minute mark when Weir (who else?) curled in a superb drive off the underside of the crossbar from just inside the penalty box.
However, goals from Hannah Eurlings and Isabelle Iliano increased Belgium's lead to 6-0 and it was down to one goal between them and Scotland.
Step up Weir again, firing low past Rubin from 12 yards and, although news came of another from Eurlings in Luxembourg, the Belgians ran out of time and goals.