Gylfi Sigurdsson's penalty in the first-half proved to be the difference on Saturday night, as Everton beat Chelsea 1-0 at Goodison Park in front of 2,000 fans.It ended the Blues' 17-game unbeaten run across all competitions and reinvigorated Everton's stop-start run. With the win, Everton moved just two points behind Chelsea in the Premier League table.Everton vs. Chelsea on TwitterFT: Everton take the points today. 😔#EVECHE pic.twitter.com/Yhc2SyU4OB— Chelsea FC (@ChelseaFC) December 12, 2020Gylfi Sigurðsson created 6 chances today, more than every Chelsea player combined (5).Vintage. 🔵 pic.twitter.com/zvZcmUuSib— Statman Dave (@StatmanDave) December 12, 2020It was turning out to be a cagey first quarter of the game before Edouard Mendy's rush of blood pinned Dominic Calvert-Lewin inside the 18-yard box. The foul left referee John Moss with no option but to point to the spot.Gylfi Sigurdsson, who has more goals against Chelsea than any other Premier League opposition, held his nerve and sent the Blues goalkeeper the wrong way.HALF-TIME Everton 1-0 ChelseaGylfi Sigurdsson’s cool penalty is all that separates the two teams at the break#EVECHE pic.twitter.com/cyeeBruSB0— Premier League (@premierleague) December 12, 2020Gylfi Sigurdsson has now scored as many Premier League goals as David Beckham and Yaya Touré (62).Joining up with some of Manchester’s finest. 🤝#EVECHE pic.twitter.com/vd6We5FMgN— William Hill (@WilliamHill) December 12, 2020That would have been a disrespectful penalty from Sigurdsson had it been saved. What's he doing. Just put your laces through it. But it went in the net so it is a "cool finish". This is just how it works.— Duncan Alexander (@oilysailor) December 12, 20206 - Gylfi Sigurdsson has scored more Premier League goals against Chelsea than he has vs any other side in the competition, scoring twice against the Blues for each the three clubs he's played for (Swansea, Tottenham, Everton). Degrees. #EVECHE— OptaJoe (@OptaJoe) December 12, 2020HT Everton 1-0 ChelseaMendy error causes Sigurdsson scoring from the penalty spot. Everton well set up to hold onto their lead. Chelsea have not done enough to really force the big chances to equalise despite dominating possession. #CFC #EVECHE— Nizaar Kinsella (@NizaarKinsella) December 12, 2020Well, at least we know Mendy is human. I thought he may have been some sort of cyborg before he finally made a mistake like that. #EVECHE— ChelseaMaven (@Chelsea_Maven) December 12, 2020Édouard Mendy has now given away more penalties for Chelsea in the Premier League than Kepa Arrizabalaga.— Squawka Football (@Squawka) December 12, 2020Most of the Chelsea forwards were being closed down by two or three Everton shirts every time they were in possession. The likes of Olivier Giroud and Timo Werner struggled to interchange passes, while Kai Havertz had an absolute shocker in the first-half.Please please come alive in the second half Kai Havertz 🔵 #CFC pic.twitter.com/lofMvP4f5B— CFC-Blues (@CFCBlues_com) December 12, 2020Havertz plays like he’s always about fall down 😭— Mod (@CFCMod_) December 12, 2020Everton defending like Prime Italy today.— Super Frank Era (@SuperFrankEra) December 12, 2020Kai Havertz, a 21 year old hasn’t adapted fully to a new league, with no pre season, congested fixtures all whilst having COVID a couple weeks ago. People have no patience these days, him costing a lot doesn’t change the factors above.— MAH (@matissearmani) December 12, 2020The visitors failed to produce anything substantial in the second-half, but Frank Lampard only turned to his bench in the 67th minute. With three strikers covering the forward line, there was an apparent lack of a cutting edge.Everton, meanwhile, defended brilliantly and set Richarlison free on the counter during the turnover of possession.Second half we have been dire!! Really would of liked Billy Gilmour in the pitch. Just have not created anything in the 2nd half. #EVECHE— Frank Khalid (@FrankKhalidUK) December 12, 2020Having all three of our natural wingers out injured is proving costly.No creativity, especially from out wide. Barely any runs in behind. No one taking players on.Need to get CHO, Ziyech and Pulisic back fit ASAP.— LDN (@LDNFootbalI) December 12, 2020Werner, Giroud and Havertz have had a combined 8 touches in the penalty box in the first 72 minutes. Outright stinkers from all 3 so far.— ExpectedChelsea (@ExpectedChelsea) December 12, 2020Mason Mount, who was one of the better performers on the evening, was denied by the frame of goal. It was the second time the goalpost came in the way of Chelsea and their equalizer.Chelsea have now gone 20 minutes without a shot against Everton.They still trail 1-0.— Squawka Football (@Squawka) December 12, 2020Mount's free-kick hits the post! 😩🔵 1-0 💠 [81’] #EVECHE— Chelsea FC (@ChelseaFC) December 12, 2020Mason and Reece - two very small positives tonight.— Simon Phillips (@SiPhillipsSport) December 12, 2020The well-earned win could open Everton's doors once again after recent struggles, while Chelsea will feel hard done by as they could have gone on top of the table with a win.They remain third, with Liverpool and Tottenham Hotspur yet to feature this weekend.FT. Big performance. Big win.UP THE TOFFEES!!! ✊💙🔵 1-0 ⚪️ #EVECHE pic.twitter.com/O6rNA3DoPY— Everton (@Everton) December 12, 2020Chelsea, Man United and Man City all drop points in the PL title race 😬Jose Mourinho's mood right now: pic.twitter.com/Q7KZLNJThV— ESPN FC (@ESPNFC) December 12, 2020Did you think Everton deserved to beat Chelsea? Sound off in the comments.