Integration of technology in language learning has become a recommendable initiative for English as Second Language (ESL) instructors. Previous studies have noted remarkable improvement of students' learning through the integration of games in classroom teaching. However, little attention has been given to the integration of games element in language classroom that particularly aims to hone students' writing skills. In response to current language learning situation related to writing skills, this current study sought for a new method of assessment in ESL context. An online game application, Kahoot, was used as the primary tool for students' assessment in an academic writing course participated by 32 ESL students in a public university in Malaysia. Qualitative research design was conducted in this study and collection of data was conducted through focus group discussion with ESL learners and a semi-structured interview with ESL instructors. The Responses from students and instructors were recorded and transcribed in verbatim. Thematic analysis of the data revealed that ESL learners found that game-based assessment is highly engaging despite of some learners' anxiety towards the use of technology. ESL instructors also highlighted the importance of learning objectives in assessing students' performance regardless of the tools used.