Myles Peart-Harris’ first goal for Swansea City proved the difference as the hosts defeated Watford at the Swansea.com Stadium.
The on-loan Brentford midfielder turned in a Ronald knockdown at the far post in the latter stages of the first half, with his strike a thoroughly deserved reward for a dominant Swans performance.
Peart-Harris had earlier hit the post, while Ben Cabango had a goal ruled out for offside and Ronald could not turn in an inviting cross at the far stick.
Watford barely threatened, even though they were improved after the break, and the Swans defended stoutly when required as they claimed a fifth clean sheet of the season and made it back-to-back wins.
Swansea had shown two changes from the weekend win over Oxford as Kyle Naughton and Liam Cullen came in for Josh Tymon and Joe Allen respectively.
The Swans had the first effort on target when Peart-Harris’ improvised volley found the gloves of Daniel Bachmann.
The hosts then created a great chance when Matt Grimes’ made the most of good pressing work to send a sweeping pass into Peart-Harris’ path.
The midfielder saw his first shot blocked, and his follow-up effort trickled onto the base of the post.
Peart-Harris was heavily involved, and his appeals for a penalty were waved away after he appeared to be pushed in the box, and he then produced a moment of magic to beat three men and deliver a fantastic cross that Ronald could not quite turn in at the far post.
Cabango then had the ball in the net after Harry Darling’s initial header had been saved, but the flag was soon up for offside.
But the Swans had the lead their dominance deserved when a deep cross was swing into the back post and Ronald headed a Goncalo Franco delivery back across goal for Peart-Harris to turn in.
The home side held that lead at the interval and Cabango saw a shot blocked early in the second half as they looked to extend their advantage.
Franco then sliced a volley over the bar after a deflected Ronald cross had fallen into his path, before Josh Key slalomed his way to the edge of the box before running out of room.
Ronald was close to catching Bachmann off his line after working hard to reach Cullen’s blocked just inside the Watford half.
The Hornets had yet to muster a shot on target but a series of corners around the hour mark gave them a rare foothold in the contest.
Darling made an excellent block as Ryan Andrews drilled a fierce effort goalwards, and then covered tremendously well to deny Kwadwo Baah a clear run at goal and force a corner.
Swansea City: Lawrence Vigouroux; Josh Key, Ben Cabango, Harry Darling, Kyle Naughton (Cyrus Christie 75); Matt Grimes (captain), Gonçalo Franco (Joe Allen 75); Ronald, Liam Cullen, Myles Peart-Harris; Žan Vipotnik (Florian Bianchini 67).
Unused Substitutes: Jon McLaughlin, Kristian Pedersen, Nathan Tjoe-A-On, Nelson Abbey, Aimar Govea, Azeem Abdulai.
Watford: Daniel Bachmann (captain), Francisco Sierralta, Mattie Pollock, Tom Ince (Mamadou Doumbia 73), Giorgi Chakvetadze, Ken Sema (Ryan Andrews 62), Pierre Dwomoh (Imran Louza 62), Vakoun Bayo (Daniel Jebbison 83), Festy Ebosele, Yasser Larouci (Kwadwo Baah 46), Edo Kayembe.
Unused Substitutes: Jonathan Bond, James Morris, Antonio Tikvic, Kevin Keben.
Referee: Josh Smith
Attendance: 12,869