Sousa has put Portuguese tennis on the map - the first player from the Iberian country to crack the ATP's top 100 and top 50, as well as the first to win a title - but has still to fully realise his potential.
Today's match should be a cracker, long overdue after some flat finals in recent years.
The 2016 decider was ruined by Sock's heavy flu virus, while the 2015 final between Jiri Vesely and Adrian Mannarino lacked memorable moments.
The 2014 final was tight - but matches featuring John Isner serving a trillion aces are never great spectacles - and David Ferrer outclassed Phillip Kohlschreiber the year before.
However, all the ingredients are in place today. Sock has got better throughout the week and played his best match of the tournament yesterday, with a clinical 6-4, 6-3 win over compatriot Steve Johnson.
Sock had come through two tough three set battles against Ryan Harrison and Jeremy Chardy - on both occasions coming back from a set down - but was dynamic on court yesterday.
His movement and court coverage was outstanding and the match featured some of the best rallies of the week, as Sock chased down every ball.
Sousa was even more impressive, in a 6-1, 7-5 demolition of Marcos Baghdatis.
Baghdatis was stunned from the start, as the Portuguese sprinted to a 5-1 lead in the first set, before rounding it out in 23 minutes.
Baghdatis offered some resistance in the second set - and had chances on the Sousa serve late in the set - but Sousa always looked more in control and converted his third match point with an ace.
The unseeded Sousa tends to fly under the radar but can't be ignored any more, as he has yet to drop a set this week.
"I feel comfortable here and the week has gone well," said Sousa. "It's a great way to start the year."
The 27-year-old Sousa credits his form with a lot of hard work in the off-season, when he completed a training block with Rafa Nadal.
"Rafa and I are good friends and he is a great guy," said Sousa. "You learn a lot from him, the way he practices and his approach to the game. He always wants to improve and works incredibly hard."
Sousa is overshadowed by footballers in Portugal, but is starting to make a name for himself.
"Unfortunately not all of my matches are live on television at home but I get a lot of support," said Sousa. "Always a lot of messages."
After last year's virus on the eve of the final, Sock declared himself fit to play today.
"I'm feeling better than last year, looking forward to feeling healthy out there and giving it my best shot, said Sock. "I feel like I am a guy that progresses well throughout the tournament and I can play better deeper into the week."
Sock and Sousa have met once before, with Sousa winning in three sets on the Madrid clay. Expect a similarly tight contest today.
