Northampton head for Christmas still in second place, if three points adrift of Saracens, having escaped the first of three difficult seasonal matches by the skin of their teeth and a dramatic intervention of a referee who managed to confuse both teams with some of his decisions.

Matthew Carley, the first graduate from the RFU's Referee Academy last August, and the first referee to officiate wearing RefCam, was controlling his sixth game in the Premiership on Saturday when he made two decisions in three minutes which turned the match first one way, then another.

First he penalised Lee Dickson, on the field only three minutes after replacing Kahn Fotuali'i, for the tackle in which the former England prop Tom Palmer – 6ft 7in and well over 18st – was upended by the current England scrum-half who is 5ft 10in and a bit over 13st, according to Twickenham, or "11½ stone tackling 23 stone" if you are Jim Mallinder, the Northampton director of rugby, who was trying to make a point.

"He went low and Tom Palmer ran over the top of him," said Mallinder, who was also unimpressed by the sending to the sin-bin of his captain on the day, the England flanker, Tom Wood, and the denial of a first-half try for the centre Luther Burrell.

Joe Carlisle, the third kicker used by Wasps, kicked the Dickson penalty to ease his side into a one-point lead but just when his Dai Young thought they were home and dry, came the penalty for early engagement at the scrum which had the Wasps director of rugby seething.

"I can't see where that one came from at all," said Young, who knows a bit about scrummaging, having played 51 Tests for Wales and three for the Lions as prop. "It took 80 minutes for a scrum penalty to come on the engagement, which is remarkable. We had reset after reset all afternoon and then in injury time we get one scrum that goes down and he penalises us straight away.

"The players didn't get what they deserved. That's a game we worked hard to win," said Young, whose side are now five places off the bottom after Stephen Myler landed his fourth penalty on a difficult afternoon for kickers and referees. Myler said: "It was tricky out there but I was able to get to grips with it."

Northampton now face Bath and then Harlequins, two other teams challenging for play-off places before the holiday season ends. By then George Pisi will have returned, allowing Mallinder to end the experiment of playing George North at outside-centre, something Warren Gatland says he is tempted to do in a future Wales lineup. The Wales coach is unlikely to get further help from Mallinder, who has already paid out £60,000 in fines this month for releasing the 21-year-old for Tests outside the official international window.

North, who also started at outside-centre for Northampton's remarkable Heineken win in Dublin a week ago, had a quiet afternoon at Adams Park and Mallinder was adamant: "Although George is very capable of moving into 13, we see him as a wing."

Wasps Daly; Helu, Bell (capt), Hayter, Varndell; Goode (Carlisle 44), Davies (Simpson, 62); Mullan, Festuccia (Lindsay, 62), Cooper-Woolley (Swainston, 62), Palmer, Launchbury, Johnson, Haskell, Jones.

Pens Daly, Goode 2, Carlisle 2.

Northampton K Pisi (G Dickson, 62); Elliott, North, Burrell, Collins; Myler, Fotuali'i (L Dickson, 73); A Waller (E Waller, 65), Haywood (Hartley, 57), Ma'afu (Mercey, 57), Manoa (Lawes, 62), Day, Clark (Dowson, 62), Wood (capt), Dickinson.

Try Day. Pens Myler 4. Sin-bin: Wood 71.

Referee Matthew Carley (RFU). Attendance 6,897