Mancini got the final contact halfway through the second half of as he tried to prevent Ademola Lookman turning in a low ball pushed into the six-yard box by using Harvey Barnes.
That introduced Leicester degree of their first ever European semi-final after Lorenzo Pellegrini had given Roma an early lead on the King Power Stadium.
The tie, which pits Mourinho against Brendan Rodgers, his one-time protege on the training personnel at Chelsea, is now poised beforehand of subsequent week's return in Italy.
Mourinho is hoping to feature the new third-tier European trophy to his collection having received Champions Leagues, a UEFA Cup and a Europa League all through his managerial profession, and Roma could not have requested for a higher start.
They went in advance on the quarter-hour mark whilst Nicola Zalewski accrued the ball on the left and powered ahead earlier than playing in captain Pellegrini to fireplace low beyond Kasper Schmeichel inside the Leicester intention.
Last season's FA Cup winners, who dropped into the Conference League after going out of the Europa League in the group level, were then dealt a blow as Timothy Castagne was forced off halfway thru the first half.
Lookman tested goalkeeper Rui Patricio from range simply after the 1/2-hour mark however it become the second-half of advent of Barnes that proved critical in getting the Premier League facet returned on stage terms.
Barnes replaced Marc Albrighton on the same time Kelechi Iheanacho was despatched on for Jamie Vardy, the veteran ahead making his first begin due to the fact early March following his modern harm setback.
It changed into Barnes who drove into the field earlier than drilling a low ball in from the left side of the location in the direction of Nigerian global Lookman. Italian worldwide defender Mancini ended up helping the ball over the line to make it 1-1.
Rui Patricio then tipped an Iheanacho shot across the post and Leicester - whose former striker Gary Lineker become watching from the stands - will have to find a way of triumphing in Rome if they're to attain the very last inside the Albanian capital Tirana on the quit of next month.
