There was no dream start to the 61-year-old Scot's return to the Goodison Park dugout as manager after a gap of almost 12 years as he was unable to make an immediate impact.
Even the emotion of the occasion could not help rectify many of the problems predecessor Sean Dyche had encountered as they failed to score in an 11th Premier League match of the season.
It was perhaps understandable, considering Moyes had only had a couple of coaching sessions, there might be a few mistakes as new ideas were put in place and one of those errors led to the goal.
Not for first time on the night Jarrad Branthwaite carelessly gave away possession on the halfway line and Morgan Rogers punished him with a through ball beyond James Tarkowski which left goalkeeper Jordan Pickford in two minds whether to come or stay.
That brief moment of hesitation probably cost him as Watkins comfortably placed the ball out of his reach to ultimately move Villa level on points with sixth-placed Manchester City.
The last Premier League game Moyes failed to win at Goodison as Everton manager was a 3-3 draw with Villa in February 2013 and he then went on to win his final six.
Newcastle's Alexander Isak has now scored in eight successive EPL games, a first for the Magpies. (AP PHOTO)
At St James' Park, Alexander Isak became the first Newcastle player to score in eight successive Premier League games as his double helped condemn Wolves to a 3-0 defeat.
The 25-year-old Sweden international opened the scoring with a deflected 34th-minute effort and then helped himself to a second after the break to take his tally to 16 goals in as many games and 17 for the season before setting up Anthony Gordon for a third.
His efforts were instrumental in securing a club record-equalling ninth successive win in all competitions for the Magpies and eased them into the top four.
For Crystal Palace, Jean-Philippe Mateta and Marc Guehi struck in the second half to beat Leicester City 2-0 condemning the Foxes to a sixth straight Premier League defeat.
Boos rang around the King Power Stadium at full-time after a result that left Ruud van Nistelrooy's side still two points from safety.
Leicester had produced a rare display of dominance in the first half but went into the break goalless despite having 11 shots, although Mateta had squandered a glorious chance to put the away side in front.
And it only took seven second-half minutes for Palace to click into gear as Mateta made amends for his miss, before Guehi wrapped up the points for Palace with 12 minutes left.
In other games, Arsenal beat Tottenham 2-1 continuing the pressure on Spurs' Australian manager Ange Postecoglou.
Following consecutive home cup defeats to Newcastle and Manchester United, Arsenal fell behind at the Emirates after Son Heung-min's 25th-minute opener for Spurs.
But they were back on level terms with 40 minutes gone when Gabriel's header from a corner rebounded off Dominic Solanke before Leandro Trossard put them ahead on the stroke of half-time.
Arsenal saw out the second half to move back into second place and within four points of leaders Liverpool, who were held to a 1-1 draw at Nottingham Forest on Tuesday.
For Tottenham, it marked a fourth defeat from their last five league matches to leave them 13th on the table, eight points clear of the relegation zone.
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