Tigers scored the first and final tries of the game through Dan Hemingway and a penalty try on the final whistle. Skipper Tom Youngs also crossed in the second half.
But they conceded six tries, including two penalty scores, under the Welford Road lights.
The visitors opened the scoring with Alex Goode’s seventh-minute penalty after Tigers were penalised at a maul.
Tigers provided an instant riposte through Hemingway as the Academy forward followed up his first-team debut in Saturday’s EDF Energy Cup win at Bath by scoring the first try of the night.
Sam Vesty’s grubber kick was half stopped by the Saracens defence but the ball popped up for Hemingway to take possession and cross on the left. Ben Youngs added the conversion from the touchline to give Tigers a 7-3 lead.
Tigers were caught offside at a ruck almost immediately from the restart and fly-half Goode kicked his second penalty.
Saracens went ahead on 30 minutes when England international full-back Dan Scarborough made ground on the right and, as he was tackled by Vesty, he off-loaded for Edd Thrower to score. Goode missed the conversion from five metres inside the touchline as Saracens ended the half 11-7 up.
They added to their lead four minutes after the restart. A succession of attacking scrums had Tigers back-pedalling and referee Martin Fox awarded the visitors a penalty try as the Leicester forwards stood up.
Tigers were reduced to 14 men shortly after when centre Tom Youngs was yellow-carded.
Goode added another penalty after 57 minutes when Tigers were adjudged off their feet at a ruck.
With Tigers reduced to 14 men again following a yellow card for Hemingway, Saracens were awarded another penalty try as the home scrum came under pressure near their own line. Goode added the simple conversion.
Tigers fell further behind moments later when Goode added a try on the right to go with his haul with the boot. He kicked the extras to put Saracens 35-7 ahead, and moments later wing James Short scored Saracens’ fifth try in the opposite corner.
Tigers pulled a try back through Tom Youngs. A series of thrusts pushed Saracens on to their own line before the ball was pushed out to the right wing and Youngs forced his way over. Younger brother Ben missed the conversion.
Saracens scored again when Brendan McKibben crossed under the posts after Thrower’s break and Goode added the extras.
But Tigers scored with the last attack of the game when they were awarded a penalty try.
Replacement Manu Tuilagi made a good break near the Saracens line but when he looked to take a return pass he was tackled without the ball just five metres from the try-line and the referee signalled a try under the posts. Replacement Elliot Read added the conversion with the last kick of the game.
Tigers: Cobden, Varndell (M Tuilagi 71), Erinle (Reed 47), T Youngs (c), Hurrell, Vesty, B Youngs; Brown, Collett (Sammons 67), Bonorino (Parkins 41), Komaisavai, Deaville, Hemingway, Bell (Everard 67), Pearson
Reps not used: Harrop, Harrison
Saracens: Scarborough, Thrower (Tirrell 50-68), Casson, Farrell (Stanley 67), Short (Tirrell 71), Goode, Wilson (McKibben 57); Lloyd, Walker, Mercey, Smith (Anderson 50-57), Spencer, Kruis (Anderson 71), George, Wray
Reps not used: Vine, Bonney
