Quins a Yarde ahead of Tigers
Nothing separated the two sides at the break after Oliver Bryant and Ben Botica had kicked three penalties apiece.
And just as it looked like Harlequins pressure would tell – with Botica slotting two early penalties in the first half – Leicester hooker Harry Thacker finished off a fine converted try.
Botica struck from the tee to restore Harlequins lead however, before Yarde seemingly made the result sure.
Replacement Freddie Burns then scored a penalty to ensure Leicester came away with a losing bonus point, but only late, desperate Harlequins defence, led by the heroic Luke Wallace, made sure of the win.
A late reshuffle to Leicester's starting XV meant the unveiling of former South Africa captain Jean de Villiers – in the centres alongside Manu Tuilagi – and a first the Premiership start for 20-year-old Bryant.
And the youngster showed he would not be overawed by the occasion by knocking over a nerve-settling penalty in the seventh minute.
But no sooner had he kicked through, Botica replied for Harlequins – with both sides still feeling each other out in a battle of attrition.
The game burst into the life in the 16th minute, with Ross Chisholm making a try-saving tackle on Telusa Veainu before Tim Visser went mightily close for Harlequins at the other end.
This contest looked like it would be won in the trenches however and after a forwards drive drew a Harlequins infringement, Bryant slotted another penalty.
Yet again Botica levelled things up for Tigers in a rare excursion into Harlequins territory, only for Bryant to respond two minutes later.
Chisholm and Yarde combined sweetly, however, before another penalty for Botica tied things up just before the half-hour mark.
Indeed, if there was ever a battle of the kickers this was it, though Harlequins went closest to breaking the try-line when Wallace couldn't find a last man with his offload.
It remained 9-9 heading into the second half and Leicester, for all their lack of an attacking edge, were putting in some defensive shift – with Bryant at the heart of much of it.
However, a penalty at scrumtime in the 46th minute saw Botica kick Harlequins ahead in the match for the first time.
The hosts kept Leicester under pressure and though a Botica slip meant a penalty fell short, he returned to the tee soon after to extend Harlequins' advantage to six points.
They would give up that lead though when a neat line-out move – with Laurence Pearce and Tuilagi at the forefront – created the space for Thacker to plunge over on the left.
Burns, who had replaced Bryant at flyhalf, nailed the conversion to nudge Leicester into the lead by one point.
But Harlequins kept putting the crush on at the scrum and the eagle-eyed Botica, with his sixth penalty of the night, hit a superb kick to restore the lead.
As the game entered its final ten minutes, Peter Betham and Sam Harrison had Leicester on the move – and forwards pressure earned a penalty.
Burns, albeit with a tricky kick, placed his effort just wide before Yarde came to the fore.
The superb Wallace forced a turnover, and Yarde kept on his feet to hare over after picking up an inch-perfect grubber from Botica, who also converted..
As ever, Leicester refused to give up and a Burns penalty brought Leicester within six, but Harlequins survived through 21 phases at the death to hang on for victory.
The scorers:
For Harlequins:
Try: Yarde
Con: Botica
Pens: Botica 6
For Leicester Tigers:
Try: Thacker
Con: Burns
Pens: Bryant 3, Burns
Teams:
Harlequins: 15 Ross Chisholm, 14 Marland Yarde, 13 Winston Stanley, 12 Harry Sloan, 11 Tim Visser, 10 Ben Botica, 9 Tito Tebaldi, 8 Nick Easter, 7 Luke Wallace, 6 Mat Luamanu, 5 Charlie Matthews, 4 James Horwill (captain), 3 Adam Jones, 2 Dave Ward, 1 Mark Lambert.
Replacements: 16 Rob Buchanan, 17 Owen Evans, 18 Kyle Sinckler, 19 George Merrick, 20 James Chisholm, 21 Sam Egerton, 22 Tim Swiel, 23 Matt Hopper.
Leicester Tigers: 15 Mathew Tait, 14 Peter Betham, 13 Matt Smith, 12 Manu Tuilagi, 11 Telusa Veainu, 10 Freddie Burns, 9 Sam Harrison, 8 Laurence Pearce, 7 Brendon O'Connor, 6 Tom Croft, 5 Mike Fitzgerald, 4 Ed Slater (captain), 3 Fraser Balmain, 2 Leonardo Ghiraldini, 1 Marcos Ayerza.
Replacements: 16 Harry Thacker, 17 Riccardo Brugnara, 18 Logovi'i Mulipola, 19 Graham Kitchener, 20 Jordan Crane, 21 Jono Kitto, 22 Oliver Bryant, 23 Jean de Villiers.
Referee: JP Doyle
Assistant referees: Roy Maybank, Wayne Falla
TMO: Sean Davey
Source: @premrugby