What is this lightning-fast tiny spider?
Many web-dwelling spiders are lightning-quick in their own web (even if they are slow/clumsy walkers outside of their web) so that doesn't help in identification.
Hard to tell from the photo, but it appears to be Cyclosa ginnaga
A better image of the specimen would help identify.
edit after comment:
Here is a gallery of observations (currently 50 of them) of cyclosa ginnaga: https://inaturalist.ca/observations?place_id=any&amp;subview=grid&amp;taxon_id=360502
All those observations were made in South-East Asia or Australia.
You could also look at Cyclosa Insulana with similar range:
https://inaturalist.ca/taxa/560706-Cyclosa-insulana/browse_photos?quality_grade=any
But I think the length of abdomen in your photo more closely resembles C.ginnaga, and also the observations of C.ginnaga more consistently show a spiral in the thick webbing while C.insulana tends to be more random.
And here is a breakdown of the cyclosa genus broken down into specific species if you want to browse other possibilities:
https://inaturalist.ca/taxa/127360-Cyclosa/browse_photos?quality_grade=any&amp;grouping=taxon_id