The second-half collapse against Tottenham was a disappointing setback in the ongoing audition for the two forwards to demonstrate their ability to play together effectively as a partnership. Unfortunately, they fell short of expectations and failed to deliver a cohesive performance.
Moments after Duran replaced Morgan Rogers, who had been taken off as a precaution after picking up a knock, Dominic Solanke netted a quick-fire double to give the hosts a two-goal lead before James Maddison made it 4-1 with a free-kick in stoppage-time.
It marked the 10th time the two Villa forwards had shared the field in the Premier League this season, with Duran featuring off the bench more than any other player so far (10), and the lack of cohesion was clear to see once again.
Villa's record with both strikers on the pitch is respectable with five wins, three draws and two losses - but it is the underlying levels of production from each player that will be keeping Emery up at night.
TrendingOf the five goals scored in these games, Duran is responsible for two, including his stunner against Everton, and Watkins has one to his name.
The pair are yet to assist each other and 60 per cent of the goals scored with both forwards on the pitch occurred during the 3-1 win against Wolves, which saw Gary O'Neil's side collapse late on.
Disrupting the flow of the team as a whole is another issue, as the loss to Tottenham clearly highlighted. Villa have nearly conceded as many goals (four) as they have scored (five) when Emery has decided to trial the pair together.
It prompts a lack of balance in the team and suppresses their individual qualities - but why?
Playing two strikers is rare to see in the modern game and Villa have shown why so far.
Watkins and Duran occupy similar spaces when on the field and are yet to build the chemistry needed to operate simultaneously.
In contrast, Rogers offers a more complementary heat map to Watkins, as he looks to drop deeper to collect the ball and drive his team forward.
The England U21 international stumbled into the role of second striker this season but Emery has also utilised others, such as Youri Tielemans and John McGinn, with the same assignment: Occupy the space behind the striker, drag defenders out of position and create space for Watkins to thrive in.
Meanwhile, Duran's priorities are more in line with his counterpart, as both look to maximise their chances of scoring.
In the small sample size of minutes Duran has seen on his own in the Premier League, Villa concede three goals per game in comparison to just one with Watkins flying solo.
The root cause of the improved defensive numbers with the England international leading the line could correlate to his work-rate off the ball.
Watkins and Rogers form a formidable partnership with their pressing and the latter ranks in the top 15 players for successful turnovers (34) as a result of this work-rate.
Duran's numbers are slightly lower and could hint as to why Villa are more susceptible to conceding when he replaces Watkins in the line-up.
These figures might also highlight why Emery continues to opt for Watkins as his first choice in the role, despite the strong numbers off the bench from his teammate.
The Villa boss is well aware that the experiment is yet to work but insisted he will keep giving Watkins and Duran the "chance" to thrive together, as he searches for a solution to his striker conundrum.
Speaking after the loss to Tottenham he was asked why he chose to play the two together, saying: "Because it is a possibility.
"I have to try to give minutes to those players on the field and how we can get better with those players. It is the process we have and we are building a team.
"We are trying to get a strong structure in everything. A situation we have to work with is those two strikers. We have to give them chances to get confidence.
"Every match is a challenge in the Premier League, Champions League and the cups. We are analysing performances and then trying to get the best decisions."
This is not the first time Watkins has struggled to gel with another striker at the club.
The same experiment was trialled on several occasions when Danny Ings was in the Second City from 2021 to 2023 and it eventually led to the striker being squeezed out of Emery's plans in the January transfer window.
Villa were a worse side during this time frame but the same issues presented themselves, as the lack of cohesion up front sent reverberations throughout the team as a whole.
Villa will be hoping to avoid a similar situation with Duran but the 20-year-old forward has been honest about his lack of patience.
Sporting director Monchi claimed no less than 40 clubs registered an interest in Duran throughout the summer and the list will have only grown given his strong showings across all competitions.
Both players are tied down to long-term contracts and both deserve a regular role in the starting line-up.
Whether or not this will materialise in the same Villa team remains to be seen.