While Mandhana has 709 rating points and Verma has 726, Australia's Beth Mooney climbed a spot to top the chart with 754 points.
Currently, Australia leads the multi-format series 6-4 and India would be required to win all the three T20Is in order to register a victory in the series.
More than 80 overs were lost due to weather over the first two days, making draw the most likely outcome of the four-day match.
Elysse Perry and Ashleigh Gardner were batting on 27 and 13 respectively at stumps.
Hopefully, it is start of something special: Australia skipper Meg Lanning on pink ball Test against India
The BCCI and Cricket Australia wish to slot in a Test in the full series they play going forward.
Jhulan Goswami returned with figures of 3/37 from her 10 overs to play a big role in India's win in the third and final ODI and was adjudged player of the match for the performance.
India, who were aiming to post 250 plus regularly to challenge the likes of Australia, could only manage 225 for eight in an innings that never got the momentum it needed.
Australian skipper Meg Lanning said on Wednesday that the absence of pace spearhead Megan Schutt leaves a hole in the squad.
Team India will travel to Australia in September to play three ODIs and as many T20Is besides their maiden Day-Night Test at Perth starting September 30.
The Australian women's team, on the other hand, are currently playing the T20 tri-series, which also involves hosts India and England.