Fetching details from the dictionary...
to make matters worse; besides; what's more; in addition; on top of that
暑いし、御負けに湿度も高い。
It's hot, and on top of that, humid.
仕事が忙しくて、御負けに体調も悪い。
Work is busy, and to make it worse, I'm unwell.
電車が遅れ、御負けにバスも来ない。
The train is late, and the bus isn't coming.