Offense wins games; defense wins championships. That's how the old saying goes, and it tends to ring true, although nobody has told Barcelona that.

Nobody wants to bet on a football game and hope that nothing happens. It goes against the entire precipice of placing a bet looking for some excitement on a match day. However, sometimes it's the smartest play in the book, especially if you know what you're looking for.

When betting on under 2.5 goals, one wants to look for a stingy defense that concedes very few opportunities and even fewer goals. So, which teams should you be looking at in Europe right now? Here are three to watch out for.

Arsenal

Arsenal conceded just 27 goals last season, and that staunch backline helped the Gunners end a 22-year wait for the Premier League title. This term, they started in similar fashion as they conceded just one in their first four games, winning each of them.

Their robust defense has seen them come in for criticism, especially toward the back end of last season. Manager Mikel Arteta was relying on his defense to cling on to 1-0 wins against the likes of West Ham and Burnley down the stretch, two teams that ultimately suffered relegation at the end of the season. But that didn't bother the Gooners one bit once the title was wrapped up.

And let's face it; why wouldn't Arteta rely on his carefully constructed back line? Center-halves Gabriel Magalhães and William Saliba may well be the finest central defensive pairing on the planet on current form, while the addition of former Aston Villa captain has only strengthened an already steely unit. At full back, the likes of Riccardo Calafiori, Piero Hincapie, and Jurrien Timber are all defenders first and foremost, as opposed to the modern full back that sacrifices defensive qualities for pace and attacking quantities.

Including their Community Shield win against Manchester City and their Champions League win against Napoli, Arsenal have kept five clean sheets in the seven games they've played this term. That makes the "no" selection on a both teams to score bet incredibly enticing. But as we found out on the Premier League's matchday five, their defense is by no means invincible.

Bookmakers had made Arsenal overwhelming favorites to successfully defend their title this term. Then, they were thumped 3-0 by Brighton at the AmEx on September 19th, a result that could prompt manager Arteta to revert to the defense-first tactic that yielded the title last season. The latest odds from sports betting sites still make Arsenal a 6/5 favorite to reign as champions again, but Arteta’s could well be favoring his back line once more in the coming weeks.

So far this term, his side has played a more free-flowing attacking game, but that result on the South Coast may well trigger the Spanish boss to tighten things up even further. That could be good news for unders bettors.

Cagliari

In recent years, Serie A has been dominated by Inter Milan. The Nerazzurri romped to the Scudetto by 11 points, and many expected them to do the same this season as well. Instead, however, the Italian top flight has a title race that looks wide open, with each of Roma, Lazio, Como, AC Milan, and Juventus all looking as though they have a genuine shot.

One team that no one had penciled in as a title contender, however, is the perennially relegation-threatened Cagliari. But the Sardinian club has built a monster defense that has seen them climb all the way up to fourth place in the standings.

The Rossoblù has conceded just two goals in their five games so far this season. Four of those games have resulted in a Cagliari win, with three of them finishing with a 1-0 scoreline. Indeed, even the one game they lost this season, away at champions Inter, finished 1-0 as Fabio Pisacane's side emerged with their pride firmly intact.

21-year-old defender Juan Rodríguez has been key to keeping the door slammed shut. He has formed a staunch partnership with Zé Pedro, while former Premier League midfielder Harry Winks has done a stellar job in adding some much-needed experience in the center of the park.

All but one of Cagliari's games have finished with fewer than 2.5 goals this season. In fact, they finished with less than 1.5 goals. Only their 2-1 win away at Atalanta and their 1-2 defeat to Verona in the Coppa Italia have seen both teams score over 2.5 goals. Bets on the "under" would have won in 72% of the Rossoblùs games this season, and that's a strike rate that should entice punters.

Lyon

Ligue 1 has long been dominated by Paris Saint-Germain, but French football's formerly dominant force looks to be making a comeback, and it's doing so on the back of a watertight defense that's conceded just two goals in five games so far this season. That team, of course, is Lyon, a team which romped to seven straight titles throughout the 2000s.

Their last title came back in 2008, and Les Gones haven't truly come close to a title since. This year though, things look different, as a three-man defense of Moussa Niakhaté, Ruben Kluivert, and Felix Bacher has strangled the life out of Ligue 1. Lyon have conceded just twice in Ligue 1 so far this season, with their 4-0 drubbing of high-flying Rennes their second straight clean sheet.

 

As such, betting "no" on the both teams to score market seems to be the best play, as Lyon can score plenty at the top end of the pitch.