A last-minute penalty kick from Rory Clegg salvaged a 9-9 draw for Harlequins in what was a cagey clash with London Irish at the Stoop.
All the points in the match came from the tee, the most crucial of which was landed by Clegg with the last kick of the game as title-chasing Irish were denied a sixth straight victory.
Prior to that, Clegg and Irish's Ryan Lamb had each stroked over two first-half penalties before Peter Hewat edged the visitors 9-6 in front with a three-pointer in the 72nd minute.
Clegg's late coup de grace means Quins stretch their unbeaten run in the league to four games but Irish lost a great opportunity to keep on the coat-tails of unbeaten leaders Saracens.
The number ten, making his first start for Quins since his summer move from Newcastle, booted the Quins in front with a fourth-minute penalty.
The 19-year-old then traded penalty misses with Lamb before the Exiles fly-half levelled the scores with his first of the afternoon, in the 16th minute.
Irish had by then settled into their natural flowing rhythm, Lamb and Seilala Mapusua particularly pleasing on the eye with midfield breaks, but they were dealt a major blow when Sailosi Tagicakibau hobbled off with an ankle injury.
The Fijian flyer is the Premiership's top tryscorer this season with six touchdowns and with fellow winger Adam Thompstone on the long-term injury list, they are now seriously short of firepower out wide.
Peter Richards - a scrum-half by trade but increasingly used as a utility back nowadays - came on in place of Tagicakibau and he saw Lamb put Irish ahead with a 25th-minute penalty.
Clegg restored parity with his second three-pointer, eight minutes before the break, but there were still a distinct lack of tryscoring opportunities out there with both defences proving obdurate.
The second half was just as tight and hard-fought, and it became increasingly obvious that it would remain a battle of the boot.
Clegg's let him down in the 50th minute when he shanked wide a penalty that had been awarded following his own clever chip behind the Irish defence that Nils Mordt ran on to, leading to the Exiles infringing at the breakdown.
Lamb was then short with a penalty attempt from just inside his own half and Irish were soon relying on the superb covering defence of Steffon Armitage to keep Quins at bay.
Mike Brown made a searing break through the left channel, leaving Alfredo Lalanne in his wake, and the England full-back looked destined for a try when he ran onto his chip over Hewat. Armitage, though, stole in to grab the ball in front of Brown and avert the danger.
Clegg dropped a goal against the left upright in the 57th minute as Quins finally exerted some pressure but the scores stayed level going into the final 20 minutes.
A raft of substitutions from both sides led to the match becoming even more fractured, and the two teams continued to make sloppy handling errors that halted a number of potentially promising attacks.
Hewat stepped up just when it mattered, though. When Quins were pinged for not rolling away at a ruck, the Australian took over kicking duties with Lamb having been replaced.
Hewat nonchalantly slotted his penalty straight between the posts from 40 metres and Irish looked to defend their lead in the last eight minutes.
They could not, though, as with a minute to go, Clegg booted over his third penalty of the afternoon to steal Quins a share of the points.
Pen: Clegg 3
For London Irish:
Pen: Lamb 2, Hewat
Harlequins: 15 Mike Brown, 14 David Strettle, 13 Gonzalo Tiesi, 12 Nils Mordt, 11 Josh Drauniniu, 10 Rory Clegg, 9 Steve So'oialo, 8 Tom Guest, 7 Neil McMillan, 6 Chris Robshaw (c), 5 George Robson, 4 James Percival, 3 John Andress, 2 Tani Fuga, 1 Ceri Jones.
Replacements: 16 Chris Brooker, 17 Aston Croall, 18 Mark Lambert, 19 Lewis Stevenson, 20 Chris York, 21 Karl Dickson, 22 Seb Jewell, 23 George Lowe.
London Irish: 15 Peter Hewat, 14 John Rudd, 13 Elvis Seveali'i, 12 Seilala Mapusua, 11 Sailosi Tagicakibau, 10 Ryan Lamb, 9 Alfredo Lalanne, 8 Chris Hala'Ufia, 7 Steffon Armitage, 6 George Stowers, 5 Bob Casey(captain), 4 Nick Kennedy, 3 Paulica Ion, 2 Danie Coetzee, 1 Clarke Dermody.
Replacements: 16 David Paice, 17 Dan Murphy, 18 Faan Rautenbach, 19 Kieran Roche, 20 Richard Thorpe, 21 Chris Malone, 22 Jamie Lennard, 23 Peter Richards.
Referee: George Clancy
Assistant referees: Roy Maybank, Andrew Pearce
Assessor: Paul Bridgman
Television match official: John Burtenshaw