The purpose of this work is to observe and analyze if a group of thirty students of an integrated English e-course could benefit from the explicit teaching of five lexical groups and the pedagogical principles behind the Lexical Approach. These low-intermediate students (CEFR, A2) took an Integrated English e-course at the School of Modern Languages, University of Costa Rica (UCR). To begin with, the target group took a short diagnostic test related to the five lexical groups to determine their prior knowledge on such aspect. To assess the level of improvement reached, the students received explicit instruction on five lexical groups as part of the writing components of this team-taught course. After this, the instructor revised 120 compositions (60 drafts and 60 final versions). Then, after intensive practice through a series of activities based on the Lexical Approach, they took a final instrument to measure how much they have learned throughout the virtual course. The results show a positive effect of explicit instruction of lexical units on student's writing outcomes and their post test.