Leicester moved above hosts London Irish and into second position in the Aviva Premiership after they beat the Exiles 23-14 on Saturday.
The win saw the visitors leapfrog Irish, although Saints remain the runaway leaders.
Toby Booth's side had not won any of their four matches in November and looked unlikely to end that run of failure as Leicester had them under the cosh by half-time.
The Tigers controlled the match territorially, as Irish made little impression.
Home fly-half Ryan Lamb had a torrid opening period. He was put under pressure by the Leicester back row as Irish looked hesitant when they had decent possession but found the Tigers defence impenetrable.
And when Irish gave away penalties, Tigers' fly-half Billy Twelvetrees was in good form. The youngster booted Leicester into a 9-0 lead with three penalties, one of which was from the halfway line.
The only try-scoring opportunity of the half came just after the half-hour when Leicester hooker George Chuter fired an attacking line-out ball over the top for flanker Thomas Waldrom to grab and charge 22 metres to the line.
However, Waldrom was called back for a crooked throw and Irish escaped.
Somehow, with the home pack struggling to keep the opposition at bay, Irish went into the break just 9-3 down as Lamb bravely held his nerve with the final chance of the half to land a huge 49-metre penalty.
Irish coach Toby Booth must have had some serious words with his side at the break because they came out with vigour and venom straight afterwards and were soon only a point behind.
Lamb was a different player to the hesitant character of the opening 40 minutes, placing two lovely touch-finders right into the Leicester danger zone.
And the ex-Gloucester number 10 was the creator of Irish's first try of the match.
It was a well-crafted move which saw big number eight Chris Hala'ufia charge up the middle before he was dragged down. Excellent home scrum-half Paul Hodgson fed Lamb who chipped over the visiting defence for wing Topsy Ojo, who beat Scott Hamilton's despairing tackle on the line.
The comeback did not last long, however. Leicester upped the pace, attacking the home pack again in the loose and providing the platform for Ireland international full-back and Leicester captain Geordan Murphy to give Waldrom another chance to score which, this time, he accepted.
Twelvetrees' conversion gave Leicester an eight-point buffer but, after another attack from Irish, this time an 11-phase move, the Tigers infringed under their posts, giving Lamb the easiest of penalty shots to reduce the margin.
Irish attacked again as the last 10 minutes approached and were rewarded when number eight Jordan Crane was deemed offside, allowing Lamb to bisect the posts with his third penalty.
But the result was put beyond doubt with two minutes to go when the Irish scrum was put under extreme pressure on their own line.
Three times the Leicester pack, with England stars Chuter and prop Dan Cole solid in the front row, forced their opponents backwards. Referee David Pearson eventually lost patience and ran between the sticks for a penalty try.
The conversion under the posts also finished off London Irish's chances of at least securing a losing bonus point as their losing streak continued and the Tigers marched on.
For London Irish:
Pen: Lamb 3
Tries: Waldrom, Penalty
Con: Twelvetrees 2
Pen: Twelvetrees 3
London Irish: 15 Delon Armitage, 14 Topsy Ojo, 13 Elvis Seveali'i, 12 Daniel Bowden, 11 Jonathan Joseph, 10 Ryan Lamb, 9 Paul Hodgson, 8 Chris Hala'ufia,7 Richard Thorpe, 6 George Stowers, 5 Kieran Roche, 4 Nick Kennedy, 3 Faan Rautenbach, 2 David Paice, 1 Clarke Dermody (c).
Replacements: 16 Brian Blaney, 17 Alex Corbisiero, 18 Paulica Ion, 19 Matt Garvey, 20 Steffon Armitage, 21 Sailosi Tagicakibau, 22 Seilala Mapusua, 23 Chris Malone.
Leicester Tigers: 15 Geordan Murphy (c), 14 Scott Hamilton, 13 Matt Smith, 12 Anthony Allen, 11 Alesana Tuilagi, 10 Billy Twelvetrees, 9 Ben Youngs, 8 Jordan Crane, 7 Craig Newby, 6 Thomas Waldrom, 5 George Skivington, 4 Louis Deacon, 3 Dan Cole, 2 George Chuter, 1 Marcos Ayerza.
Replacements: 16 Rob Hawkins, 17 Martin Castrogiovanni, 18 Peter Bucknall, 19 Ed Slater, 20 Steve Mafi, 21 James Grindal, 22 Jeremy Staunton, 23 Manu Tuilagi.
Referee: David Pearson