This paper compares rhetorical structures and citation use between seven Ph. D. students' (＂novice＂) dissertations and seven published writers' (＂expert＂) research articles in the discipline of mechanical engineering in Taiwan. We focused on the introduction sections and compared their move-step structures as well as forms and functions of citations. While the expert writing shows higher citation density, mainly adopts a non-integral format, and emphasizes Move 1 (establishing a territory) and Move 3 (presenting the present study and its purpose), the novice writing predominantly focuses on Move 1. Both groups emphasized the steps of topic generalization, literature review, and niche establishment. It is therefore shown that novice writers mainly cite sources to give credit, but experts use citation to support their claims or ideas. While novices often cite references in isolation, published writers synthesize different sources to establish links among findings. Unsurprisingly, experts know more about mechanical engineering and related topics, and can also frame their own findings in light of contributions made by other researchers. Our findings lead to a clearer understanding of the contrastive genre structure and citation practices between novices and experts, and have pedagogical implications for teaching ESP to novice engineering writers.