With competence-based approach establishing in education, new attitudes to teaching and learning are gaining ground, and of paramount importance is becoming the need to change the attitudes and practice of assessment of students' learning outcomes, which are now to embrace the practical skills the students have to master, namely, the individual language mastery in fulfilling the communicative task set. When teaching non-native speakers to write original texts in a foreign language, a teacher faces a major challenge which lies in ensuring that the students effectively develop the required writing skills in order to be able not only to express their ideas correctly grammar- and vocabulary-wise, but to precisely convey the message they intend to convey. To address this challenge, action research was conducted, which was done in response to a new curriculum requirement that the undergraduate students of all specialisms had in their final year to present a synopsis of their graduation project in English both in writing and orally, given that on the whole the instruction in the institution takes place in the Russian language. The background prerequisite for the research was the observation on the part of the teachers of English for academic purposes, whose responsibility was to guarantee that the course participants successfully build the required skills, that no matter how meticulous their grading of the students' work was and how detailed their comments were, there was little progress made by students whose level of mastery of the English language was lower than the desired B2 level. Looking for new tactics that could improve the situation, the flipped classroom approach was scrutinized and a study was conducted to check the hypothesis that immediate personalized feedback given to students in person in the classroom could improve the achievement of the intended learning outcomes. As the number of contact hours is limited, the theory of academic writing was predominantly provided in the form of reading matter and PowerPoint presentations available for students on-line or sent to them via e-mail, and the contact hours as such were devoted to group discussions of the prepared written work in accordance with criterion-based assessment schemes developed by the teacher followed by peer assessment in small groups and, finally, by the individual student-teacher sessions aimed at the achievements in the particular assignment and defining the areas that needed improvement. The analysis of the results displayed by the course participants amounting to 60 students at the end of the academic year proved that immediate personalized feedback given to students in the classroom ensures building the desired competence in conveying the background, problem statement, suggested methods and anticipated results of their planned academic project, with failure rates dropping significantly, thus substantiating the correctness of the flipped classroom approach when grading and commenting takes place in the classroom in person. Further research will concentrate on refining the assessment criteria so that make peer and self assessment of the students more instrumental.