Jansenius agrees with the Thomists on how efficacious grace works
Thesis XLI. Jansenius and his followers, moreover, teach the same as the recent Thomists about the way in which Christ's healing and efficacious grace works in human wills and moves them to act. With them they hold that the efficacy of this grace is absolute, and that it does not depend on, or wait for, the consent of free choice in order to achieve its effect.
It is, they say, the conqueror of the human heart, and such that no one can resist it. The effect for which God supplies it is inseparably joined to it, and no heart, however hard, rejects it, since it is given precisely to take away the heart's hardness. It does not leave the will evenly balanced but carries it off with the greatest power, and so rules the human will inseparably and indeclinably. Much to the same effect can be read in Jansenius throughout the eight books of De gratia Christi Salvatoris, above all in the third.
Latin
XLI. Porro Jansenius & qui eum sequuntur, eadem cum Thomistis recentioribus docent, circa modum quo Christi gratia medicinalis & efficax in voluntates humanas operatur, easque ad agendum movet. Nempe cum illis volunt efficaciam gratiae illius esse absolutam, nec a consensu liberi arbitrii pendere, & eum expectare, ut effectum suum sortiatur. Illam esse cordis humani victricem, & talem cui nemo valeat resistere. Eam inseparabiliter adjunctum habere effectum ob quem a Deo praebetur: Et a nullo corde quantumvis duro respui, quia ideo praestatur ut ipsa cordis durities auferatur. Illam non relinquere voluntatem in aequilibrio, sed potentissime secum abripere: adeoque illam voluntati humanae inseparabiliter & indeclinabiliter dominari. Quibus similia multa legere est apud dictum Jansenium totis octo libris de gratia Christi salvatoris, praecipue libro tertio.