(CNN)Just when you thought the Arizona Cardinals were running off with the NFC West division title, the Los Angeles Rams might have just thrown a spanner in the works.
Rams quarterback Matthew Stafford threw three touchdowns and the LA defense was able to do just enough to stop the Cardinals to hold on for a 30-23 win on Monday Night Football.
Odell Beckham Jr., Van Jefferson and Cooper Kupp each had touchdown receptions and Stafford finished with 287 yards on 23-of-30 attempts.
The game continues Kupp's excellent season -- the 28-year-old wide receiver leads the league in receiving yards and racked up another 123 on Monday.
Kupp had at least 90 receiving yards for the fifth straight game, equaling the longest run over the past 70 seasons, according to NFL Research. He went level with NFL Hall of Famer Michael Irvin in the 1995 season and Odell Beckham Jr. -- now his teammate with the Rams -- in 2014.
After the game, Stafford called Kupp "fantastic."
"I missed him on a couple -- I wish I would have put a couple out in front to give him a chance to run," Stafford said in his ESPN postgame interview. "Great player, great teammate for us. Does a lot of the dirty work for us, too. I'm just excited for our team and we gotta continue to build on this."
The Rams were without a host of their important players after they were placed on the Reserve/Covid-19 list. Some of the absentees included star cornerback Jalen Ramsey, starting running back Darrell Henderson, starting right tackle Rob Havenstein and tight end Tyler Higbee. Ramsey said in a tweet that he feels "fine/normal."
The result prevented the now 10-3 Cardinals from becoming the first team to clinch a playoff spot this season and means the Rams are now just one game behind the NFC West leaders at 9-4.
Monday's result means that this season -- the first ever 17-game season -- is only the third without a clinched postseason berth through Week 14 since the NFL moved to a 16-game season in 1978, according to NFL Research -- the others coming in 1993 and 2014.
The Rams defense was able to slow down Cards quarterback Kyler Murray and the rest of the red-hot Arizona offense.
Superstar defensive lineman Aaron Donald finished with three sacks -- including one to clinch the victory as time expired in the fourth quarter -- while Leonard Floyd and Ernest Jones both intercepted Murray once.
"That's what the best do. They play their best when the best is required," Rams coach Sean McVay said afterwards.
"We talk about competitive greatness all the time and this guy is the epitome of competitive greatness. Really proud of Aaron (Donald). Not at all surprised."
In addition to the Rams players added to the Reserve/Covid-19 list, the NFL reported an overall increase in the number of positive cases around the league.
Monday saw 37 positive Covid-19 tests from players around the NFL, a league source tells CNN. ESPN's Adam Schefter was first to report that figure.
In the two-week span between November 14-27, the last publicly released testing data from the NFL showed 29 positive tests from players.
A Monday memo from the NFL that CNN obtained says that Tier 1 and Tier 2 staff who have previously been vaccinated and are eligible under CDC guidelines must receive a booster shot no later than December 27. This mandate does not apply to NFL players. Tier 1 and Tier 2 staff are coaches and anyone that has direct contact with players.
On December 2, the league stated that 94.4% of its players were vaccinated along with "nearly 100%" of other NFL personnel.