Pitchside monitors were used for the first time in the Premier League as Norwich City earned a crucial 1-0 win in their fight for survival over Bournemouth at Carrow Road on Saturday, in a match where both sides had a man sent off.
Teemu Pukki dispatched the penalty down the middle, easing the home crowd's nerves.
Bournemouth pressed for an equaliser after the break and they got a boost as Ben Godfrey was sent off with 14 minutes remaining after referee Paul Tierney was advised by VAR to have another look at Godfrey's tackle on Callum Wilson.
After the Professional Game Match Officials Limited, the body that manages elite referees, issued guidance for referees to use the screens this week, Tierney took a second look and brandished the red card, having initially shown a yellow.
The home side held on nonetheless for the win, moving them to within three points of Bournemouth in 19th place, with Eddie Howe's men now three points from safety after a 10th defeat in their last 12 league games.
"There is no magic wand," Howe said. "It is a case of sticking together and working hard.
"We are in that moment where anything that can go wrong will. We know how big this next one is."
Billed as the ultimate six-pointer down at the bottom as 19th and 20th-placed teams faced off, the hosts were given a pre-match boost with top goalscorer Pukki fit to start for the first time since New Year's Day.
Coming into the match in such woeful form, Bournemouth looked short of confidence and struggled to create any openings of note before Cook used his arm to make the block that ended his afternoon.
Pukki slotted home from the spot as Norwich looked in command going into the break with that numerical advantage.
Wilson missed a glorious chance to equalise midway through the second half but could not connect with Ryan Fraser's low cross, before the visitors were given their technology-assisted lifeline.
Godfrey looked to have got away with a scything tackle on Wilson, but Tierney changed his mind after heading to the monitor.
Evening up the numbers was not enough to inspire the visitors, however, as a nervy Norwich held on.
"The win was important for the team and for confidence," Pukki said. "There is a big road ahead but we are ready to fight."