After Toyota disbanded in 1984, Arnaiz followed Jaworski in a controversial move to Gilbey's Gin (now known as Barangay Ginebra San Miguel). Reprising their old backcourt partnership in Toyota, the duo turned the Gins into a perennial contender. However, he was sidelined due to a knee injury and was placed in the injured list but, was part of the line-up, during the early part of 1986 Open Conference when Ginebra San Miguel won its first PBA title. He quietly retired from basketball shortly afterwards. He won 10 championship in his illustrious PBA career, 9 with Toyota and 1 with Ginebra San Miguel.