The second seeds' opponents may be ranked outside the top 900 in the world, but they struggled to break them down in the opening set. Tied at 3-3, Heliovaara and Patten had to break point chances which they failed to take, before the opener eventually headed for a tiebreak.
Neither pair were as clinical on their serve in the tiebreak - the Finn and Brit lost serve twice, but crucially, they broke Evans and Searle's serve three times and claimed a 7-4 tiebreak win, and a 7-6 first-set success.
Both pairs were even stronger on their own serve in the second set, barely dropping a point and not coming close to being broken as the title holders took a 5-4 lead.
But with the finish line in sight, Heliovaara and Patten found another gear in the 10th game of the set, forcing a first match point of the contest, which they duly took to secure a 7-6, 6-4 victory, in a time of 1 hour 21 minutes.
The duo move onto the Second Round, where they will either face another British partnership in Billy Harris and Marcus Willis, or Alexander Bublik of Kazakhstan and Flavio Cobolli of Italy.
Heliovaara will also be in action in the mixed doubles alongside Kazakh partner Anna Danilina - they begin their campaign on Friday against Sem Verbeek and Katerina Siniakova.