Can a paper be rejected because another paper (by someone else) based on its arXiv preprint extends the result?

Suppose that I put a paper to Arxiv and submit to a journal at the same time. Someone extends my result and clearly cites my paper. This is totally fine. They submit it to a journal. For whatever reason in the review process, their paper is published before mine is accepted. Do I now have to worry that the referee will reject my paper on the grounds that a better result exists, even though they acknowledge that they get the idea from my result?