Myles Dorrian's late conversion miss denied London Irish a losing bonus point against a powerful Leicester side at Welford Road.
The host's strong scrum was a key factor in the 20-11 win over an Irish team which sits second bottom of the league.
Leicester hit the lead ten minutes in, when a penalty try was awarded as Irish's scrum creaked five metres from their own line, giving Martin Fox no option but to award the score.
The try was no less than the home side deserved, as the Tigers made clear their intent by electing to put three kickable penalties into the corner prior to the try.
Irish hit back halfway through the first period, as Australian international James O'Connor scored his first points in an Exiles shirt to get the visitors on the board. He was on target again minutes later after an extended period in The Tigers 22.
The visitors continued to struggle at scrum time though, as Irish conceded another penalty, kicked by Flood, which gave The Tigers a four-point lead at the break.
Flood's boot kept the scoreboard ticking over, as the England international hit the first penalty of the second half to give the Tigers a 13-6 lead.
TMO Trevor Fisher then saw his first involvement in the game, as he disallowed a try for Niall Morris, who had charged down O'Connor's kick to touch down.
After a ten-minute spell of constant scrums, Irish were forced into conceding yet another penalty try, with their scrum wheeling to seal the win for Leicester.
A late try from Fergus Mulchrone gave Irish a sniff of a bonus point with a minute to go, but after the missed conversion, Shane Geraghty hit a drop goal wide with the last kick of the game to give the Tigers a 20-11 victory.
Leicester's win pushes them up the table towards the chasing pack, whilst Irish still continue to struggle, losing their 6th game of the season.
Tries: Penalty Try 2
Cons: Flood 2
Pens: Flood 2
Yellow Card: Kitchener
Pens: O'Connor 2
Yellow Card: Yapp
Leicester: 15 Scott Hamilton, 14 Niall Morris, 13 Matt Smith, 12 Dan Bowden, 11 Miles Benjamin, 10 Toby Flood (c), 9 Ben Youngs, 8 Jordan Crane, 7 Julian Salvi, 6 Jamie Gibson, 5 Graham Kitchener, 4 Louis Deacon, 3 Fraser Balmain, 2 Tom Youngs, 1 Boris Stankovich.
Replacements: 16 Neil Briggs, 17 Tom Bristow, 18 Dan Cole, 19 Sebastian De Chaves, 20 Thomas Waldrom, 21 David MÃ©lÃ©, 22 Owen Williams, 23 Adam Thompstone.
London Irish: 15 James O'Connor, 14 Topsy Ojo, 13 Fergus Mulchrone, 12 Eamonn Sheridan, 11 Marland Yarde, 10 Shane Geraghty, 9 TomÃ¡s O'Leary, 8 Chris Hala'Ufia, 7 Blair Cowan, 6 Jebb Sinclair, 5 George Skivington (c), 4 Ian Gough, 3 Leo Halavatu, 2 David Paice, 1 John Yapp.
Replacements: 16 Jimmy Stevens, 17 Matt Parr, 18 Jamie Hagan, 19 Nic Rouse, 20 Danny Kenny, 21 Guy Armitage, 22 Myles Dorrian, 23 Darren Allinson.
Referee: Martin Fox
Assistant referees: Peter Huckle, Nigel Carrick
Timekeeper: David Hudson
Television match official: Trevor Fisher