The intended sacrament for this communion was likely the Eucharist. Baptism inherently washes away sin, but sin was never a part of the plan, so Eucharist would have been the only planned sacrament for inclusion into the body of Christ. Both sacraments remediate sin and provide communion with Christ.
In the Eucharist Christ’s purpose is to make communion, and in doing so remediates (venial) sin into virtue, in order to make the communion. In baptism Christ remediates our sin by making it into his own virtue, which also results in our communion with him.
Recall the last supper in which Jesus shared in the virtue and sin of the apostles by communion with them. That night at Gethsemane Jesus could not propagate or deflect this sin which was being presented to him, nor could he participate in the sin. The sin was presented to him by his human senses, emotions, and reason; his divine will reformed the apostles sin into his own virtue, thus providing union with himself.