He also warned observers to keep to within their mandate saying the airport is open for those who go astray.
Zimbabwe has held one of the most peaceful election campaigns which ended today.
It is holding crucial harmonised elections on Monday at which voters will select their president, Member of Parliament and councilor.
Addressing his final rally at the National Sports Stadium in Harare, Mnangagwa said his new administration had brought about democratic space which had seen some 133 political parties register, 55 of which are contesting the elections with 23 candidates vying for president.
Movement for Democratic Change Alliance leader Nelson Chamisa has stated several times that there will be chaos if he is not declared the winner.
The Zimbabwe Electoral Commission said presidential election results will be announced on 4 August but Chamisa and some of his lieutenants have been urging their supporters to picket the polling stations from Tuesday.
Mnangagwa urged his supporters to welcome international observers who have been allowed into the country but warned the observers not to dabble in the country’s politics saying the road to the airport is open.
Mnangagwa whose last rally seemed more aimed at the international community said his party is going to win Monday’s elections because the people had already witnessed how serious his administration is over the last eight months when he was completing former President Robert Mugabe’s term.
“It will be systems go, go and go, once we get our own mandate on Monday,” he said.