Bruno Fernandes scored his first goal for Manchester United and created two more as the Red Devils extended their unbeaten run to six matches in all competitions with a 3-0 Premier League victory over Watford.
The £62 million (A$121 million) January signing from Sporting CP put in a performance that made his fee look like a bargain, winning and scoring a first-half penalty to break the deadlock against a battling Watford team before creating superbly taken goals from Anthony Martial and Mason Greenwood.
United survived some nervous moments and Watford had an equaliser ruled out for handball before Martial doubled their advantage, but the invention and craft of Fernandes has given Ole Gunnar Solskjaer's men an edge they lacked for so much of this season.
Defeat leaves Watford in the relegation zone and without a win in six matches in all competitions, but manager Nigel Pearson will take some comfort from a strong attacking performance that might have delivered a different outcome but for some poor finishing.
Troy Deeney might have put Watford ahead after three minutes when Nemanja Matic and Harry Maguire allowed Victor Lindelof's blocked pass to run through to the Hornets captain, but he hesitated, and Luke Shaw dispossessed him just in time.
Abdoulaye Doucoure hit the side-netting from a tight angle as Watford continued to prise open a faltering United defence and, when the hosts countered, Aaron Wan-Bissaka missed from 12 yards after Ben Foster parried Dan James' angled drive.
The pace of the game slowed before exploding into life five minutes before half-time when Fernandes burst into the Watford box where Ben Foster sent him sprawling, and the Portuguese midfielder's hopping run-up and cool low finish put United ahead from the spot.
Watford had the ball in the net five minutes after the restart when Maguire lashed it into the roof of his own net under pressure from Deeney, but Craig Dawson playing the ball with his arm in the build-up meant the goal was ruled out.
Six minutes later, Fernandes turned provider, threading a pass through to Martial whose drag-back fooled Etienne Capoue before his immaculate chip saw him beat Foster at the second attempt.
United's third was the pick of the goals, Greenwood starting a move that ended with Fernandes rolling the ball to him just inside the box and he cracked an unstoppable shot into the top corner of the net off the frame of the goal.
Solskjaer sent on Odion Ighalo for his home United debut against his former club and he hit the post six minutes from time but by then the game was comfortably won as hopes of a possible Champions League return continued to grow around Old Trafford.
What does it mean?
One win in three home league matches hardly feels like great form but United are just three points behind fourth-place Chelsea, while Watford, who are 19th, remain one point adrift of safety and still without a league win at Old Trafford in their history.
Fernandes brings out United's best
The arrival of Fernandes has given the likes of James and Greenwood a creative lynchpin and, after showing his finishing prowess, the 25-year-old brought the best out of Martial and Greenwood.
Deeney made to rue early miss
Sluggish and sloppy in the opening 20 minutes, Deeney eventually grew into the game but only after he had missed Watford's best chance of the game.
Watford host champions elect Liverpool at Vicarage Road on Saturday before United's trip to Everton on Sunday. The Red Devils are in Europa League action against Club Brugge at Old Trafford three days earlier.