Rangers turned on the heat in the chilly capital of the Highlands yesterday and kept the pressure on Celtic at the top of the Clydesdale Bank Premier League with a three-goal second-half burst that left Inverness Caledonian Thistle bludgeoned and bedraggled.

Pedro Mendes may have broken the deadlock seconds after the interval with the sweetest of strikes but it was Kris Boyd who provided the killer touch with two superbly executed goals late on to take his tally to 20 goals in 21 games this season.

Boyd admitted last night that it was Mendes’s goal that turned the game and allowed Rangers to progress in a pulsating second period in which they had the home side reeling.

“Inverness did well in the first half,” Boyd said, “and towards the end of the half had a couple of chances and could have scored. We had a chat at half-time and we knew we had to do better and we did, with three goals.

“The message at half-time was that we had 15 minutes to improve or a few of us were coming off. Pedro’s great strike just after the break settled us. I am delighted with the goals I’ve scored this season but we’re five points behind in the league so it’s not that good. We need to keep it going and hope we can get ourselves back to within touching distance of Celtic.”

For Caley Thistle the picture is bleak, anchored as they are at the foot of the table and suffering their sixth successive defeat and with only one win at home this season. They wilted under the second-half pressure from the visitors and could find no answer to the increase in power and pace the Ibrox side exerted after having taken time to get into their stride, surrendering to what Craig Brewster, their manager, conceded was a world-class goal from Mendes.

Brewster still has the backing of the Inverness board but he will know that nothing less than victories over Partick Thistle in the Homecoming Scottish Cup this weekend and against Hamilton Academical, rivals at the foot of the league table, the following week, will ease the strain under which he has been working.

“There is pressure on managers,” he said, “whether you’re at the top of the league, to win titles, in mid-table, to get into the top six, or, like us, at the bottom of the table. I’m no different to any other manager and the board of directors wouldn’t be backing me by agreeing to bring in new recruits if I didn’t have their support.”

The brisk, early exchanges of yesterday’s clash promised much, with crisp passing and a sense of purpose from both sides in the near-Arctic temperature of the far north. And so focused were the players that they would not have noticed that a power cut after 15 minutes play had knocked out the floodlights, not to say the radio transmission and the laptops of the press.

Certainly, neither Roy McBain nor Iain Vigurs could be accused of being distracted as they teamed up to punish the Rangers defence and force Allan McGregor into the most acrobatic of saves two minutes later. McBain’s perfectly-placed cross from the right brought a bullet of a header from his teammate who, after McGregor’s stop, was handed a second bite of the cherry, only to have that effort cleared off the line by Madjid Bougherra. Then, with Inverness confidence high, Don Cowie’s ferocious strike from the edge of the area battered against McGregor’s chest as the Rangers goalkeeper scrambled to get to the ball.

That was all to change within 24 seconds of the restart, however, as Nacho Novo, from his position wide on the left, drained the Inverness defence with his pace before feeding Mendes in the area via the backheel flick of Kenny Miller, and the Portuguese midfield player placed the ball high into the net to relieve the tension among the visitors.

The Rangers touchpaper had been lit and Mendes, Barry Ferguson and Novo began to show their worth as the home midfield, for the first time in the game, appeared unsettled.

Chris Burke’s introduction as a replacement for Miller upset the Rangers rhythm for a time, although when the winger put Boyd through, the striker managed to produce a dangerous, angular shot, despite the attendance of David Proctor. And if Ryan Esson, the Caley Thistle goalkeeper, did well to stop that effort with his legs, he had to be even more alert minutes later as Ross Tokely intercepted a Mendes ball across goal and almost sent it into his own net.

By now, the Ibrox men were running the show and Inverness took on the form of a ragged, out-of-touch outfit, underlined when Steven Davis sent Boyd clear in the area for the striker to deliver with a low, forceful strike past Esson in the 81st minute.

The enigmatic striker doubled his tally six minutes later when he headed home Burke’s cross as Rangers took a quick free kick while some Caley Thistle players argued why it had been awarded.

Inverness (4-5-1): R Esson 6 R Tokely 5 D Proctor 6 G Munro 6 R Hastings 5 R McBain 7 R Duncan 6 D Cowie 6 I Black 6 I Vigurs 5 A Barrowman 5 Substitutes D Imrie 6 (for Black, 65min), A Rooney (for Vigurs, 73), J Duff (for Tokely, 85). Not used M Fraser, L Djei-Zadi, A Sutherland, G Wood.

Rangers (4-4-2): A McGregor 8 K Broadfoot 7 M Bougherra 7 D Weir 7 S Papac 7 S Davis 7 P Mendes 7 B Ferguson 7 N Novo 7 K Miller 5 K Boyd 8 Substitutes C Burke 6 (for Miller, 62min), S Whittaker (for Mendes, 78). Not used N Alexander, K Lafferty, A Niguez, A Velicka, J Fleck.

Referee D McDonald. Attendance 7,056