Mithali said only against New Zealand the team became a bit complacent after wrapping up the rubber.
Chasing 206 after Brunt's five-wicket haul, England won by eight wickets.
Brunt took four wickets in a crippling spell that saw India go from 129/2 to 150/7.
With the series out of their reach, Knight is now focussed on at least bagging two crucial points from the third and final game against India.
Jhulan also said that she is enjoying her rhythm since the South Africa tour last year.
Ecclestone will also miss the following tour of Sri Lanka (three ODIs and three T20Is) from March 16.
Shikha Pandey (4/18) and Jhulan Goswami (5/30) broke the back of the England top and middle-order.
Pandey and senior pacer Jhulan Goswami (4/30) wreaked havoc with the new ball to bowl out England women for 161.
Mithali also lauded Jemimah Rodrigues, saying the 18-year-old Mumbai youngster has forged a good combination with the settled Smriti Mandhana.
The India women's ODI skipper also saw the plans to conduct U-19 and U-21 World Cups for women as an advantage.