I ran across this sentence in a news article:
O’Rourke y Cruz aseguraron sus nominaciones al ganar las elecciones primarias de sus respectivos partidos.
I see that they used "al ganar". Is this a typo or is there really a grammatical feature that allows the placement of a definite article before a verb? If such a feature exists, I'd like to know how it works, preferably with a pointer to an external source to back up the explanation.