Bale scored twice in the second half to move into second place on the all-time list of Wales goalscorers with 24.
His double took him past Trevor Ford and Ivor Allchurch on 23 and to within four of record marksman Ian Rush, as Wales enjoyed their biggest win in a competitive fixture since beating Azerbaijan 4-0 in 2003.
Moldova were billed as durable opponents despite their poor recent record, but first-half goals by Sam Vokes and Joe Allen – his first for Wales – broke their resistance.
Wales fans were in expectant mood after their finest performance at a major tournament in the summer and Chris Coleman’s side had risen to 11th place in the Fifa rankings on the back of that Euro 2016 display.
Moldova were way down in 165th spot and had won only once in their previous 21 matches, but they had not conceded more than two goals in a game since losing 4-0 to England in September 2013.
That defensive organisation suggested that Wales might need to be patient to probe for an opening, but they had strong claims for a penalty after seven minutes.
Bale and Andy King worked an opening for Chris Gunter who fell under Alexandru Dedov’s clumsy challenge but Israeli referee Liran Liany showed no interest.
Gunter continued to show adventure down the right and the wing-back’s cross fell for Joe Ledley, who found space to shoot straight at Moldova goalkeeper Ilie Cebanu from 18 yards.
Cebanu required some lengthy treatment after colliding with Vokes, but it was Wales who were becoming increasingly concerned with some of Moldova’s strong-arm tactics which left Bale in a crumpled heap on a couple of occasions.
Wales were dominating possession but Moldova stood firm until Bale’s cross exposed an aerial weakness and Vokes planted a firm header past Cebanu.
Six minutes later Wales had the comfort of a two-goal cushion after Cebanu had shovelled Bale’s dipping shot around a post.
Moldova struggled to clear the corner and the loose ball fell to Allen, inset, who beat both Cebanu and Igor Armas’ despairing attempted clearance on the goal-line.
The visitors’ hopes of getting back in the match were ended within five minutes of the restart when Ion Jardan played a ball blindly straight into the path of the unmarked Bale. He strode on and comfortably chipped Cebanu to end the game as a contest, to move alongside Ford and Allchurch.
Hal Robson-Kanu came on to replace Vokes for his first football this season after his search for a club ended on transfer deadline day when he joined West Brom. Bale was still there, still running hard and still hungry for goals, with the 27-year-old looking to close the gap on Rush even more.
King went closer with an effort which had Cebanu scrambling across his goal and the goalkeeper then just about held on to Robson-Kanu’s low effort.
But Bale claimed his 24th goal for his country when he was barged over in the box in stoppage time and coolly stroked home the penalty.