Substitute Jhon Duran scored a late winner as Aston Villa opened their Premier League campaign with victory at West Ham.

Duran latched on to Jacob Ramsey's and slotted the ball into the bottom corner with 11 minutes remaining, a few weeks after the striker was reportedly the subject of two failed transfer bids from the Hammers.

Amadou Onana had opened the scoring on his Villa debut when the Belgium midfielder was left unmarked in the box to head home Youri Tielemans' corner after four minutes.

West Ham got back into the contest before the break when Matty Cash was adjudged to have fouled Tomas Soucek after a tangle in the box.

Lucas Paqueta stepped up and slotted the resulting penalty into the bottom left corner, with his stuttering run-up causing Emiliano Martinez to dive the wrong way.

However, Duran had the final say as Villa eventually made their dominance pay.

Duran replaced England striker Ollie Watkins, who had looked sluggish after minimal pre-season training, with half an hour remaining and it was the substitute who made the decisive contribution.

Reports, external throughout the summer suggested that Duran was on his way to east London, with the Colombian striker even reprimanded by Villa after doing a 'crossed Hammers' gesture with his arms on social media.

However, the move ultimately did not materialise with West Ham instead opting to sign forward Niclas Fullkrug, and the decision came back to cost the hosts.

Morgan Rogers had a low strike well saved by Alphonse Areola while John McGinn fired inches wide for Villa, before Duran's goal secured a deserved three points.

"We believe in him and his potential," Emery said of Duran.

"We are open to working with him like he did today, helping the team, being available when we need him and today he was fantastic.

"Some mistakes we have to accept and of course not repeat it. At the beginning I wanted him here and nothing changed after the match today. We know his potential and we know if he is leaving the offer is too good for the club. But I don't want him to leave."

West Ham struggled to get into the game in the first half and were lucky not to be punished further before they equalised.

Leon Bailey raced through on goal and past the onrushing Areola but his angled shot struck the post rather than finding the gaping net.

The Hammers were given a chance to equalise when Cash's foul on Soucek in the box resulted in a penalty being awarded.

After a quick video assistant referee (VAR) check, it was given, which is an example of a new rule for this season called "Referee's Call" which reaffirms a high bar for VAR intervention. It means subjective decisions will not be refereed again after a decision has been made by on-field officials.

West Ham threw on Fullkrug, for his debut, as well as Danny Ings as they went with two up front in an attempt to find an equaliser.

Another substitute making his Hammers debut, former Leeds winger Crysencio Summerville, swung in an enticing cross with minutes remaining which was headed towards goal by Ings but saved by Villa goalkeeper Martinez.

The Hammers missed an even bigger chance to snatch a draw in the dying seconds as Soucek hooked over from close range.