Romelu Lukaku's transfer value has increased by almost £50m since his summer move to Manchester United, according to the latest report from the CIES Football Observatory.

Lukaku, 24, joined the Old Trafford club for a reported fee of £75m during the summer transfer window, tasked with becoming the focal point of Jose Mourinho's attack following Zlatan Ibrahimovic's long-term injury.

The Belgium has already begun to repay that fee in earnest, having scored 11 goals in his first 10 appearances for the club, helping United climb back to the summit of the Premier League table where they sit joint top with neighbours Manchester City.

According to CIES, who specialise in the scientific estimation of transfer fees in the professional game, Lukaku's blistering form is reflected in a sharp increase in his value.

Before his move from Everton to United, the striker was valued at €102.7m (£91.5m), which has now soared to €158.5m (£140.52m) – an increase of 54%.

Kylian Mbappe, who joined Paris Saint-Germain on loan from Monaco ahead of a permanent switch next summer, has seen his value increase by €50m, while Paulo Dybala, who has scored 12 goals in 10 games across all competitions this season for Juventus, has increased by €47m.

Lukaku's teammate Marcus Rashford was valued at €71.8m by CIES in June. But after his excellent start to the season which has yielded five goals and four assists in 11 appearances, his value has soared to €98.6m – seventh in the world ranking list.

Like Lukaku, Alvaro Morata has enjoyed a sublime start to life at his new club following his arrival at Chelsea from Real Madrid, racking up seven goals and two assists in nine appearances. CIES estimate his value has now increased by €24.7m, rising to €85.2m.

United have been in the race to sign Morata before suddenly turning their attention to Lukaku with his incredible form appearing to justify that decision early on.

Lukaku meanwhile is on international duty but his participation in Belgium's two 2018 World Cup qualifying dead rubbers against Bosnia and Herzegovina and Cyprus is in doubt after undergoing a scan on an ankle problem.

Although the scan revealed no fracture, Jose Mourinho may be hopeful Roberto Martinez doesn't call upon the forward with United facing a trip to arch-rivals Liverpool following the conclusion of the international break.