After leading by a set and a break in the middle stanza, Alcaraz needed to regroup after Tsitsipas dominated the end of the game.
The Barcelona Open is one of the more important tournaments before the Roland Garros, therefore players will be eager to improve their game in a competitive setting on clay.
With the French Open only a few weeks away, Tsitsipas will be looking to take his game to the next level.
The third seed had a standout week, playing consistent and aggressive tennis to win his first title since winning in Lyon last May.
Zverev won a gold medal in the men's singles event, which has managed to elude those two superstars in an individual capacity.
Returning to the Monte-Carlo Country Club this week, the defending champion expressed his confidence and excitement.
Tsitsipas sealed the first set with the match's first break in a six-deuce game, claiming his reward for consistent return pressure throughout the set.
In a tense match at Hard Rock Stadium, both men showed off their creative shotmaking, with the picks of the bunch coming in the second set.
Sonego won his first Challenger title on October 17, 2017, when he defeated Tim Putz at the 2017 Sparkassen ATP Challenger.
Overall, he's won a total of 6 titles - four in singles and two in doubles but where he can improve is in his Grand Slam showings.