Inter paid the price for fielding an inexperienced second-string side and were beaten 3-0 by Rubin Kazan, though Rodrigo Palacio hit the woodwork.
These two sides were joint leaders of the group and already qualified going in, so the only thing to be decided was who would finish top. Andrea Stramaccioni did not seem to be concerned, as he fielded a second string side with many young and inexperienced players.
The gamble immediately hit a problem when Rubin took the lead at the second minute. Juan Jesus tried to clear an Alan Kasaev cross out for a corner, but instead hit it on to his own upright and Gokdeniz Karadeniz was quick to pounce for a tap-in.
Yet there was also bad news for Rubin, who lost Roman Eremenko to injury moments later. Inter tried to fight back and threatened with Philippe Coutinho and Alvaro Pereira attempts turned out for a corner and 18-year-old Marco Benassi drilling off target from distance.
Nerazzurri defenders did enough to stop Vladimir Dyadyun turning to get his shot away in the box, while at the other end 19-year-old Andrea Romanò wasted by firing wide from a promising position and Coutinho’s touch was too heavy after he had dribbled past two men.
Acknowledging the lack of experience, Stramaccioni introduced Rodrigo Palacio and Javier Zanetti for the second half. Within the opening minute, Walter Gargano’s snapshot had tested the goalkeeper and Palacio drilled wide soon after.
Coutinho went through thanks to a give-and-go with Palacio, but his strike missed the target. Palacio was unlucky not to draw Inter level on 65 minutes, as he sprung the offside trap on an Andrea Ranocchia pass only to see his daisy-cutter crack against the upright.
Bad news for Ranocchia, who had just returned from an injury lay-off and requested a substitution.
Coutinho burst past two players with some wonderful footwork and flicked the ball over them, but the finish was scuffed into the arms of the goalkeeper.
Rubin Kazan held on under pressure and doubled their lead in the final minutes with Rondon, who sprung the offside trap to go one-on-one with 17-year-old Donkor and drill past the goalkeeper.
Substitute Rondon added a third in stoppages when set up by Gokdeniz Karadeniz in the six-yard box.
Rubin Kazan 3-0 Inter
Scorers: Gokdeniz Karadeniz 2 (R), Rondon 86, 92 (R)
Rubin Kazan: Ryzhikov; Kuzmin, Sharonov, Bocchetti, Ansaldi; Gokdeniz Karadeniz, Orbaiz, Natcho, Kasaev (Tore 61); R Eremenko (Carlos Eduardo 8); Dyadyun (Rondon 59)
Inter: Belec; Silvestre, Ranocchia (Donkor 73), Juan Jesus; Benassi; Jonathan, Gargano, Romanò (Zanetti 46), Alvaro Pereira; Coutinho, Livaja (Palacio 46)
Ref: Skyerven (NOR)
Think you know your Italian football? Share your knowledge, tips and comments to win cash prizes in OLBG's tipster competition - £11,000 to be won monthly!