Pakistan took an unbeatable 2-0 lead in the three-match series with another thumping 59-run win in Sharjah on Sunday.
They won the first game by 111 runs at the same venue on Friday.
Pakistan, who play the last match in Abu Dhabi on Wednesday, need to beat the West Indies 3-0 to rise one place to eighth, displacing their opponents (currently eighth) to ninth.
Hosts England and the top seven teams in one-day rankings on the cut off date of September 30 next year will automatically qualify for the 2019 World Cup.
The two remaining teams will join eight Associates to feature in the qualifying round in 2018.
Ali said the series win put Pakistan in the right direction of rebuilding.
“It takes time to improve things. You need patience to lift a team. We started the rebuilding process after the 2015 World Cup and it takes one-and-a-half to two years so we are going towards that,” said Ali.
Ali replaced Misbah-ul-Haq who along with allrounder Shahid Afridi retired after the World Cup last year.
But Pakistan were whitewashed 3-0 in Bangladesh last year in Ali’s first series as captain and lost 4-1 to England earlier this month.
That raised calls for his sacking but Ali felt changes halted the team’s progress.
“No matter how many captains you change if you want to rebuild the team it takes one-and-a-half to two years.
“Our nation doesn’t have the patience, they want to win instantly. If you don’t win they get frustrated and want change. As a nation we have to take responsibility. It’s easy to look at things in hindsight and call for changes,” said Ali.
Ali said his team was getting right combinations.
“We are getting allrounders who have brought depth in batting and we are scoring 300 plus,” said Ali whose team posted a big 337-5 in 50 overs on Sunday.
“We are executing plans in bowling which is good, energy levels are high and with wins you lift your confidence. We have played well in the last five to seven matches,” said Ali of Pakistan’s three one-day and four Twenty20 wins this month.
Dismissed for a first-ball duck and nine in the two matches against West Indies, Ali hopes he strikes form sooner than later.
“My series against England was better and I scored runs there. I am playing well in the nets so it will take one innings to come in form because my confidence level is high.”