Few could blame Dean Ryan for his latest referee-bashing tirade following Dave Pearson's erratic display.

In trouble so many times for publicly criticising officials during his coaching career, the Gloucester boss probably has his own reserved parking space at Rugby Football Union disciplinary hearings.

But this time – although Gloucester must take some of the blame for their poor clearance kicks – Pearson didn't help the Cherry and Whites' bid for a third straight victory.

Gloucester did go back to the summit but thanks only to a losing bonus point at the Stoop after Tom Williams dived over with four minutes left.

But this match was riddled with mistakes from one of England's top officials Pearson.

And, as his raging eyes followed Pearson's every move, Ryan often left his seat at the top of the Quins main stand to vent his frustrations at the fourth official on the touchline.

The Gloucester head coach was far from happy with Pearson, especially when the Northumberland referee penalised the Gloucester scrum under their own posts despite dominating the set piece.

And later Pearson failed to see a knock-on by Quins from where the hosts began the period of possession for their match-winning try.

Ryan said: "On the back of our work-rate we deserved the win. I thought we put ourselves under pressure which increased the work-rate but I'm very disappointed with a couple of decisions which led to the try.

"That compounded some of own contributions. We didn't kick that smartly.

"But I thought from the high-ball there was a knock-on. I thought it was a clear knock-on. I don't understand why it wasn't.

"It was difficult to see how a scrum that had shoved them back off five previous balls gets turned over under its own sticks. Our scrum is pushing and their scrum is on the right. Again this is a crucial decision."

Pearson made more mistakes during the match – he didn't award Iain Balshaw the mark despite most of the main stand hearing the Gloucester full-back's shout.

He then gave a penalty 10 metres in-front of where the original offence took place after Luke Narraway had been penalised for not rolling away. To compound Gloucester's woes, Quins were gifted another easy shot at goal when Pearson found a Cherry and White forward guilty of dissent after their dominant scrum had been twisted underneath its own posts.

But justice was seen to be done as Harlequins replacement fly-half Chris Malone was terribly off-target with the two kicks at goal from these penalties.

Yet Quins should have been on the way to a comfortable victory had they built on fly-half Nick Evans' seventh minute try and conversion.

But despite dominating territory and possession for long periods, Quins led by only a point at the break after centre Olly Barkley replied with two penalties. Gloucester, forced to clear from deep inside their own half, could have led at half time had the bounce of the ball gone their way on 18 minutes. But three-quarters Henry Trinder and James Simpson-Daniel failed to gather Barkley's punt for touch that wickedly bounced in-field with no-one between them and the Quins line.

Barkley hit Gloucester in front with a 49th minute penalty, but the visitors struggled to build any concerted pressure on Quins after failing to clear their lines properly and were often penalised by Pearson.

Gloucester were hanging on and, after being gifted possession by a Pearson mistake, the hosts grabbed the match-winning try with four minutes left when Williams darted home from the side of the ruck. Malone converted.

Ryan's side enjoyed their best attacking periods in the closing seconds but, with Quins putting them under pressure, were forced into mistakes as they tried to snatch victory.

Harlequins: M Brown (U Monye 57); D Strettle, G Tiesi, J Turner-Hall, T Williams; N Evans (C Malone 40), A Gomarsall (J Poluleuligaga 70); C Jones, G Botha, M Ross, O Kohn (J Evans 53), G Robson, C Robshaw, W Skinner (capt), T Guest. Reps not used: A Croall, M Lambert, N McMillan.

Scorers: Tries – Evans, Williams. Cons – Evans, Malone.

Gloucester: I Balshaw; C Sharlpes, H Trinder (A Allen 43), O Barkley, J Simpson-Daniel; C Spencer (R Spencer 66), R Lawson; N Wood, A Titterell (O Azam 51), G Somerville, M Bortolami (A Eustace 51), A Brown, L Narraway, A Hazell (A Satala 80), G Delve (capt). Reps not used: A Dickinson, M Foster.

Scorers: Pens – Barkley 3.

Referee: D Pearson. Att: 12,638.