Wilfried Singo's early header was the difference between the two teams as Villa tasted defeat for the first time in six outings in all competitions.

Monaco had only won two of their last 11 matches, including back-to-back defeats in the Champions League, but now have their eyes on securing progress to the knock-out stages.

The defeat dropped Villa from fifth to seventh provisionally, but they are still in with a chance to qualify automatically for the last-16 with a top-eight finish.

Unai Emery's side host 21st-placed Celtic in their final league phase match next week.

Monaco sit ninth on 13 points, level with Villa and fourth-placed Arsenal.

They conclude their league phase campaign with a visit to Italian champions Inter Milan -- sixth on 13 points after six matches -- knowing nothing but a win will do if they are to avoid a play-off spot.

Both teams could still miss out on progression with 25th-placed Paris Saint-Germain and 26th-placed Stuttgart six points behind and having two games in hand.

Villa goalkeeper Emiliano Martinez's every touch was booed by the home support in the early stages -- the crowd not having forgotten his role in Argentina's 2022 World Cup final victory over France.

To their great delight, Monaco's opener came via a botched save by the Argentinian as he could only parry Thilo Kehrer's header from a corner up in the air and Singo pounced to nod home from close range on eight minutes.

But Martinez soon showed his class with a sprawling dive to claw away Maghnes Akliouche's whipped effort shortly afterwards.

Unai Emery's side took firm control of the encounter.

Villa draw blank 

And they came within inches of levelling in first-half added time following excellent build-up play by Emiliano Buendia, but Majecki got down quickly to deny Ollie Watkins.

Monaco countered and could have gone into the break leading by two, only for Akliouche to sky his shot when one-on-one with Martinez.

The match picked up at the start of the second period where it had left off in the first with Morgan Rogers flashing a strike narrowly wide of the post, before Akliouche had a goal disallowed for offside at the other end.

As often this season, Emery turned to Jhon Duran from the bench to give his side a spark, sending on the Colombian 11 minutes after the interval in place of winger Bailey.

With Watkins and Duran both on the pitch together, Villa boasted a striking duo with 22 goals between in all competitions this term.

But it was Rogers and Matty Cash who combined to create Villa's best chance of the half so far, the right-back dragging his effort across goal and wide after being played in on 69 minutes.

Despite their opposition's attacking riches, Monaco looked the more likely side to score in the final 20 minutes.

Aleksandr Golovin rippled the side netting from a tight angle in the 88th minute.

Duran then attempted a bicycle-kick in the crowded box in the 92nd minute but his highly-ambitious effort flew well over the bar as Monaco ground out a vital win.