The challenge of student retention in introductory-level computing classes is a key contributor to the lack of diversity in computing fields. While teaching assistants (TAs) play a critical role in these classes, their role in supporting student retention is yet to be explored. We employed a special TA, a retention TA (RTA), who focuses exclusively on supporting students who are at risk of failing the course. RTAs target students who are retaking the class or underperforming in exams or assignments. This contrasts with regular TAs, who focus on grading and other standard duties. In Spring 2024, four RTAs were assigned to four different introductory-level computing CS1 and CS2 classes. At the end of the semester, we analyzed student attendance records and compared the performance of students who sought help from RTAs to the overall class performance. In two of the four classes, students who engaged with RTAs performed better than the class average. We share experiences from one of those classes, including specific RTA strategies that may have contributed to student success, such as personalized communication, reviewing course content, and helping students get started on assignments.