Tottenham’s talisman, who has scored a combined 25 goals for club and country this season, joined up with his international team-mates later than the rest of the squad after suffering from a virus earlier in the week, but returned trained on Thursday.
And Bale impressed during the opening 45 minutes at Hampden Park but felt he could not carry on as he struggled to overcome the illness - with initial rumours being of a lower-back injury - and the 23-year-old has taken to Twitter to confirm his fitness.
"Just clearing the air ... nothing wrong with my ankle," Bale wrote. "I came off at [half-time] due to the stomach virus I've had all week. Should be OK for Tuesday.
"Great win by the lads tonight, hopefully we can take this on to the next game."
Wales fell behind on the stroke of half-time when Grant Hanley’s smart run inside the area saw him lose his marker and home past Boaz Myhill.
However, an Aaron Ramsey penalty and Hal Robson-Kanu winner inside two second-half minutes turned the game on its head – and manager Chris Coleman commended his team’s resolve to claim three vital points.
"We had to be patient," Coleman told Sky Sports. "We felt for the first 30 minutes we dominated. The players had given everything we asked of them.
"We just got back to it in the second half. We started popping it off and got our just rewards."
The win over Scotland leaves Wales third in Group A, seven points off joint leaders Belgium and Croatia heading into Tuesday’s visit of Igor Stimac’s men.