Using jq how to correctly read a pair containing a backslash character?

I have a script with reading from json file in this way:

jq -c '.[]' input.json | while read pair; do   echo "$pair" | jq -r '.[0]'done;

The above throws `parse error: Invalid numeric literal at line 1, column 17` when input.json content is:

[    ["\\", "bslash.jpg"]]

This does not happen with other characters. Only on this, which is escaped.
How to correctly parse the content with jq?