Last year's Europa Conference League runners-up are in the driving seat for the Eredivisie title approaching the final few weeks of the season, sitting five points clear of PSV Eindhoven in first place with a game in hand.
Arne Slot's men defeated Ajax 3-2 in De Klassieker just before the international break, but the Amsterdam outfit gleaned revenge with a 2-1 win during Wednesday's KNVB Beker semi-final.
In a chaotic contest that had to be stopped twice due to crowd disorder, Man United were one of several clubs with representatives in attendance, according to The Mirror.
The Red Devils were supposedly monitoring the progress of Turkey midfielder Kokcu and Mexico striker Gimenez, both of whom played the full 90 minutes of that semi-final defeat.
Kokcu joined the Feyenoord academy in 2014, and he was made captain of the Dutch title contenders for the 2022-23 season following the departure of Jens Toornstra, despite being just 22 years of age.
The 2000-born midfielder has shone with the armband during the current campaign, scoring 12 goals and providing three assists in 37 matches across all tournaments from the middle of the park.
Kokcu's efforts have helped the Rotterdam club to reach the quarter-finals of the Europa League, where they will take on Roma, who beat them in last year's Europa Conference League final.
The Turkey international - who was previously strongly linked with Arsenal - has totalled 32 goals and 25 assists in 166 outings for Feyenoord, who have him under contract for another two years.
However, Benfica are already thought to be readying a £31m approach for Kokcu as a replacement for Enzo Fernandez, who joined Chelsea for a nine-figure sum in January after a protracted period of negotiations.
Meanwhile, 21-year-old striker Gimenez left boyhood club CD Cruz Azul last summer to join Feyenoord, and he has hit the ground running in Europe with 17 goals from 36 matches in his debut campaign.
The Argentina-born forward - who represents Mexico at international level - has netted five goals in the current Europa League campaign, level with Union Saint-Gilloise's Victor Boniface and only behind Marcus Rashford's six.
Gimenez's contract with Feyenoord runs until the end of the 2025-26 campaign, but the Eredivisie leaders are supposedly prepared to accept a modest fee of £18m in the upcoming window, having paid just €4m (£3.5m) for his services last summer.
As well as Man United, Tottenham Hotspur are also said to have been watching the pair with eagle eyes, as were Brentford, West Ham United, Brighton & Hove Albion and Leicester City.
Representatives from top European clubs such as Borussia Dortmund, Lyon, Wolfsburg, Sevilla, Atletico Madrid and Monaco also took their seats in the stands for Feyenoord's semi-final triumph.