London Irish ended Saracens' ten-match unbeaten run in the Guinness Premiership with a 23-19 win at the Madejski on Sunday.
The visitors led until 10 minutes from the end, despite wasting opportunities to extend their six-point advantage by attempting failed drop-goals.
Elvis Seveali'i darted over to punish them and put the hosts ahead for the first time in the match, with Malone making no mistake from the conversion.
Saracens knew nothing could prevent them going into 2010 as league leaders following their best-ever start to a Premiership campaign - nine wins and one draw from 10 outings.
And they took no time edging ahead at the Madejski, Alex Goode drilling over a long-range drop-goal with just two minutes on the clock.
That lead grew in the ninth minute when Irish scrum-half Alfredo Lalanne saw his attempted clearance kick from a five-metre lineout charged down by Hugh Vyvyan. Justin Melch scooped up the rebound and flopped over the line and Glen Jackson's conversion gave Sarries a 10-0 cushion.
But it did not last long as Irish finally shed their cobwebs and produced a five-pass attack up the middle that finished with Steffon Armitage sending Chris Hala'ufia between the posts. Malone's conversion signalled an upturn in the atmosphere as the subdued crowd finally came to life.
Saracens weathered a mini-storm as a result before increasing their lead on 22 minutes with a Jackson penalty, awarded because Irish were caught offside in numbers by referee Dean Richards.
The official promptly found Saracens guilty of an identical offence within two minutes as Irish swarmed around their 22, and Malone reduced the deficit to three points.
Jackson, however, made Irish pay for a flurry of indiscipline at a 29th-minute breakdown, driving the resultant penalty high between the posts from wide on the right.
Irish had an opportunity to reduce the gap yet again on 36 minutes after Vyvyan was penalised for pulling down in a lineout. But this time Malone's penalty attempt drifted wide of the near post.
With nothing separating the teams in the set-piece, it was easy to see how both go into the new year with genuine title hopes as they changed ends having given attending England coaches Brian Smith and John Wells plenty to think about.
Irish took the initiative at the start of the second half, and their pressure earned another penalty after 43 minutes. But Malone was again off target, his second miss out of four kicks at goal.
But Irish kept pressing, earning two further penalties. The first was driven into touch by Malone to set up an attacking platform, and Saracens were forced to go offside again to prevent serious damage. This time Malone made no mistake with a confident 47th-minute strike.
That man Jackson, however, regained his side's six-point gap just two minutes later with a fine penalty strike from wide on the right.
He had the chance to give his team the cushion of a two-score lead on 55 minutes, but the angle this time proved too acute and Jackson's attempt from out on the left just faded outside the near post.
Irish were throwing everything into their attacks and tempers flared when the Saracens' defence refused to buckle. Referee Richards had to break up two outbreaks of 'handbags' which actually served to rouse the crowd even further.
Saracens then drove upfield and had their hosts on the back foot but, for the second time in the game, they elected to go for a drop-goal that failed - a choice that earned a chorus of booing from the home support.
Having pinned Irish back for fully seven minutes, Saracens conceded a penalty at the breakdown and left the home half without a point to show for all their pressure.
Then an attempted Saracens interception was adjudged to be a deliberate knock-on and Malone set up a fierce finale with a penalty goal on 66 minutes.
Irish took the lead for the first time on 70 minutes.For once, the Saracens defence failed to slam the door as Seveali'i burst between three failed tackles to score on the left, and Malone added the extras.
For London Irish:
Tries: Hala'ufia, Seveali'i
Cons: Malone 2
Pens: Malone 3
Pens: Jackson 3
Drop goal: Goode
London Irish: 15 Delon Armitage, 14 Tom Homer, 13 Elvis Seveali'i, 12 Seilala Mapusua, 11 Peter Hewat, 10 Chris Malone, 9 Alfredo Lalanne, 8 Chris Hala'Ufia, 7 Steffon Armitage, 6 Richard Thorpe, 5 Bob Casey (c), 4 Nick Kennedy, 3 Paulica Ion, 2 David Paice, 1 Clarke Dermody.
Replacements: 16 Danie Coetzee, 17 Dan Murphy, 18 Faan Rautenbach, 19 Kieran Roche, 20 George Stowers, 21 John Rudd, 22 Peter Richards, 23 Ryan Lamb.
Saracens: 15 Alex Goode, 14 Rodd Penney, 13 Kameli Ratuvou, 12 Brad Barritt, 11 Chris Wyles, 10 Glen Jackson, 9 Justin Marshall, 8 Ernst Joubert, 7 Justin Melck, 6 Wikus van Heerden, 5 Hugh Vyvyan, 4 Steve Borthwick (c), 3 Richard Skuse, 2 Fabio Ongaro, 1 Matias Aguero.
Replacements: 16 Schalk Brits, 17 Rhys Gill, 18 Carlos Nieto, 19 Mouritz Botha, 20 Andy Saull, 21 Moses Rauluni, 22 Derick Hougaard, 23 Richard Haughton.
Referee: Dean Richards