Leicester moved into the Aviva Premiership play-off places by ending London Irish's winning run.
The Tigers had to withstand some huge pressure from Irish in the dying minutes but just held on to record a deserved victory by scoring three tries to none.
The win raised the Tigers into fourth position in the league, moving above Harlequins as it becomes increasingly likely that those two sides will contest for the final play-off place.
Irish were aiming to record their fourth consecutive win in the Premiership but after an even first half, they fell away as Leicester became more dominant.
Irish had to rely on four penalties from James O'Connor and one from Ian Humphreys for their points. Australia international O'Connor, however, missed three kicks at vital times, which would have made the game a whole lot tighter for Leicester.
The visitors were always the more likely try scorers and there were three in total scored by Ben Youngs, the impressive Vereniki Goneva, and a controversial one for Logovi'i Mulipola. Owen Williams added a penalty and conversion.
Irish made only one change to their starting line-up after last week's impressive win at Wasps. Scrum half, Tomas O'Leary, sent off in that game was suspended so he was replaced by Darren Allinson. Marland Yarde returned from a long injury lay-off to take up a place on the bench.
Ed Slater returned from England squad training to captain Leicester for the first time. He partnered Louis Deacon in the second row with Deacon being recalled to take the place of Graham Kitchener. Williams was preferred to Toby Flood at fly-half.
Leicester made a dreadful start. They failed to collect the kick off before immediately conceding a penalty which O'Connor kicked to put Irish in front.
The lead was short-lived as Leicester scored their first try after eight minutes. A succession of five-metre scrums placed huge pressure on the home pack which created a simple try for Youngs.
Irish were dealt a further blow when prop Jamie Hagan left the field with a rib injury to be replaced by Leo Halavatu. Despite this, they should have regained the lead but O'Connor missed a kickable penalty.
However O'Connor made no mistake with another opportunity to give Irish a 6-5 lead at the end of an even first quarter.
The home side then produced their best spell of the match forcing Leicester to concede a number of penalties, one of which O'Connor kicked to reward their pressure.
O'Connor carelessly gave away a penalty in his own 22 with Leicester having no hesitation in choosing an attacking line-out. It paid dividends with Mulipola deemed to have finished off a forward drive.
The try was awarded by the TMO but replays seem to indicate that Irish captain, George Skivington, had managed to prevent the score by getting a hand in under the ball.
From the restart, Irish suffered another setback when centre, Eamonn Sheridan, was yellow carded for taking out Matthew Tait in the air but Leicester could not capitalise before half-time so the visitors led 10-9 at the interval.
Six minutes after the restart, Leicester took advantage of Sheridan's absence by scoring their third try. Goneva brushed aside some weak Irish tackling to run 30 metres to score an excellent solo try which Williams converted before adding a penalty.
Yarde was introduced by Irish, who should have reduced the arrears but O'Connor missed a simple penalty which left them 20-9 adrift going into the final quarter.
O'Connor was successful with another attempt as Irish attempted to move the ball wide to Yarde in the hope that he may provide some attacking spark. He ran strongly on a couple of occasions but the Tigers' defence was not to be breached.
Leicester's replacement, Thomas Waldrom was sin-binned with ten minutes to go but O'Connor again could not kick the resulting penalty.
Flood was introduced by Tigers to steady the ship before Humphreys took over the goal-kicking to succeed with one, but the change was too late as O'Connor's misses ultimately proved to be crucial.