The goals made the Harambee Stars Striker go down in history books, as the first ever Girona player to claim a hat-trick in the La Liga league.
He scored three goals in a span of 22 minutes to help Girona to ninth place on the league table following a massive win over bottom-placed Las Palmas in a one-sided match.
The Kenyan had over the months grown frustrated in the club by warming the bench but was handed a chance as a 46th-minute substitute.
Olunga took the opportunity, plundering in a treble, his first La Liga goals that will leave his head coach Pablo Machini Diez with some soul searching work to do ahead of the next round of fixtures.
His third goal was as a simple as it came after spotting an opportunity in the 79th minute, he rightly positioned himself in the box and poked home the rebound albeit from a high angle to lay his marker.
His other goals came in the 57 and 70th minutes hardly able to believe his luck, he was then left with an easy finish to complete his hat-trick 11 minutes from the end — three goals in 23 minutes and the first ever hat-trick by a Girona player in La Liga.
A 24th-minute penalty by Stuani set the tone for the huge victory before the unplayable Olunga sliced through the Las Plamas defence like a knife on butter, with swiftly taken treble, while Borja Gracia also found the mark with a 63rd-minute strike.
The win hoisted Girona to position nine with 26 points on the Spanish La Liga table. They’ve played 19 games so far, winning seven, drawing eight and losing seven.
Olunga’s next test is against the mighty Atletico Madrid who are placed second on the log.