Juninho, who grew in influence as Leicester tired, brought Atletico level with 21 minutes remaining. Christian Vieri settled the issue, at least for the night, by converting a strongly disputed penalty.
When the clubs last met, in the fledgling Cup-Winners' Cup, Britain had "never had it so good" with Macmillan, while Spain was still under Franco's iron heel. Leicester began as if intent on righting a 36-year wrong, and sent their 3,000 followers into raptures by scoring after 12 minutes.
The circumstances suggested Atletico had not done their homework. Leicester are renowned for exploiting dead-ball situations, yet when they worked a short corner Steve Walsh was unmarked as he nodded Garry Parker's pass into the danger zone. Marshall shot home from six yards.
Martin O'Neill, to no one's surprise, detailed Pontus Kamark to track Juninho. The Swede's discipline and stamina meant that the former Middlesbrough player's primary function in the first half was to oversee Atletico's set-pieces.
From his short corner, Juan Vizcaino had a drive turned over by Kasey Keller. At another, Daniel Prodan headed wide. Then, from a free-kick 30 yards out, Juninho was frustrated to see Keller swoop to his right to save.
Only once, when Jose Luis Caminero failed to connect with Juninho's exquisite chipped pass, did the Brazilian threaten from open play. Meanwhile, Marshall's participation was curtailed by Prodan, who left the striker needing five stitches in a gashed calf.
Leicester's tendency to press the man in possession in swarms also restricted the opportunities for Atletico's other major summer recruit, Vieri, to show why Raddy Antic paid Juventus pounds 12.5m for him.
By contrast, Steve Claridge had scarcely touched the ball as Marshall's replacement before Emile Heskey's cushioned header gave him a chance to lob the Spanish goalkeeper. The ball landed on top of the net.
Atletico began to conjure moments of genuine menace after the interval, and Keller saved brilliantly from Kiko. Steve Guppy, a winger operating as an orthodox left-back, blocked the first follow-up, and Vieri's attempt was also diverted behind.
The mounting pressure reaped a decisive reward. Juninho struck a deflected equaliser after another blur of passes involving Kiko. Before Leicester could recover their composure, Guppy was adjudged to have tripped Delfi Geli. After an altercation involving a dozen players, Vieri scored emphatically from the spot - his first goal for Atletico - but Leicester were not dissatisfied to leave with an away goal.
Atletico Madrid (4-3-1-2): Molina; Geli, Prodan, Toni (Josi Mari, 58), Andrei; Lardin, Vizcaino (Bejbl, 64) Caminero; Juninho; Vieri, Kiko. Substitutes not used: Futre, Bogdanovic, Roberto, Jaro (gk).
Leicester City (4-1-3-2): Keller; Prior, Elliott, Walsh, Guppy; Kamark; Izzet, Lennon, Parker (Fenton, 71); Marshall (Claridge, 30; Campbell, 90), Heskey. Substitutes not used: Whitlow, Cottee, Savage, Andrews (gk).
Referee: R Helge-Olsen (Norway).Reuse content