The reason was simple: the pal in question is a Burnley-supporting neighbour and the Leeds United manager did not fancy having to relive what was shaping up to be an afternoon to forget for his side.
United were trailing 2-0 and such had been the Clarets' dominance in the final 15 minutes or so of the first half that a beating every bit as emphatic as those suffered against Barnsley or Cardiff City earlier in the season did not seem entirely out of the question.
A little over an hour later, however, and the picture had changed dramatically with Leeds having mounted a spectacular comeback to claim all three points.
Second-half goals from Max Gradel, Luciano Becchio and Jonny Howson meant that Grayson could not wait to get back to his home village just over the Lancashire border in North Yorkshire and toast victory with, fittingly, a bottle of Claret.
He said: "A few of my neighbours are Burnley fans and were all here (at Turf Moor).
"I was due to go for tea with a couple later on.
"One is a close friend, who brought my son to the game.
"At half-time, it seemed like he was going to have the bragging rights. But now we have won, he can get the wine in – a nice Claret."
United's amazing second-half fightback was the fifth time Grayson's side have come from behind to claim all three points this season.
It also enhanced their burgeoning reputation as the Championship's great entertainers with the five-goal thriller at Turf Moor meaning a staggering 79 goals have been scored in Leeds's 23 league and cup outings this season.
Just why an average of almost 3.5 goals are being scored in every United match is easy to see with the abundance of attacking players at Grayson's disposal meaning they pour forward in numbers.
The flipside is a back four that is prone to making individual errors is often left exposed, as proved to be the case in a contest with Burnley that was so open that the goal tally of five could easily have been doubled with steadier finishing by both teams.
The tone of the afternoon was set inside the opening minutes as play raged from one end to the other at breakneck speed.
Leeds were the first to threaten with Gradel wasting a gilt-edged chance before two minutes had elapsed, the Ivory Coast winger shooting wide when it seemed easier to hit the target after being found in space by Robert Snodgrass.
Clearly not wanting to be outdone in front of their biggest crowd of the season, Burnley fashioned their first opening of the afternoon just 60 seconds later when Alex Bruce's late block denied Wade Elliott.
The frantic pace continued as, first, Gradel wasted another great opening by shooting instead of squaring the ball to an unmarked Becchio and then Kasper Schmeichel had to bundle Chris Iwelumo's shot round a post.
A goal was clearly coming, the only question being which of these two attack-minded outfits would find the net first.
In the end, it was the hosts who broke the deadlock as slack United marking allowed Andre Bikey to power Ross Wallace's corner goalwards just before the half-hour.
Becchio did manage to block the effort but Brian Easton smashed the rebound into the net.
The defending – or lack of – had been horribly reminiscent of earlier in the season when a game against Leeds was enough to leave an opposition striker salivating at the prospect of boosting their goal tally.
Further embarrassment for the Leeds back-line came shortly before half-time when Bruce was muscled off the ball by Jay
Rodriguez, who went on to beat Schmeichel with ease.
Two goals down, the visitors clearly needed a lift and it came seven minutes after the restart when Snodgrass whipped over a cross that Becchio diverted towards Gradel, who made up for his earlier profligacy by firing past Lee Grant.
Suddenly, Leeds sensed the comeback was on and, as Burnley visibly wilted, the move of the game brought the equaliser as Paul Connolly played a neat one-two with Howson before rolling an inviting cross for Becchio to score at the far post.
Roared on by a vociferous army of travelling supporters, United poured forward in search of the winner as Bradley Johnson shot narrowly wide and Snodgrass struck the crossbar.
A jinking run and cross from Snodgrass was then hacked to safety by Clarke Carlisle before the moment more than 4,000 Yorkshire visitors had waited for arrived five minutes from time as Howson was allowed to run from halfway before shooting past Grant from 20 yards.
There was still time for further drama as Ross McCormack went close before substitute Steven Thompson twice squandered stoppage-time chances to ensure Grayson could look forward with relish to polishing off his second Claret of the day just a few hours later.
Hero: Robert Snodgrass
Back to his best form after injury, the Scot ripped Burnley apart time and time again with his intelligent use of the ball and close control. Desperately unlucky not to get on the scoresheet with his curled effort at 2-2 striking the crossbar.
Villain: Chris Iwelumo
Not quite on a par with his miss for Scotland v Norway but he must wonder how he headed wide with the score 2-1.
Key moment: 94th minute
Such was the ease with which both sides created chances, the result was in the balance right up until the end with Kasper Schmeichel needing to save at full stretch from substitute John Guidetti deep into stoppage time.
Ref Watch: Russell Booth
A game billed on the front of the matchday programme as 'War of the Roses' is never going to be easy to officiate and, at one point, Booth seemed set to lose control. Also had a strange aversion to booking anyone from the home side.
Not for the first time this season a Leeds game could have finished 5-5 and neither side could have complained at the result. A remarkably open game in which neither defence impressed.
Quote of the day
You should have gone Christmas shopping.
– An inspired if rather premature mocking chant aimed at the away fans after Burnley had gone 2-0 ahead.
Leeds United v Queens Park Rangers; Saturday, December 18, 2010; Championship.
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