SEATTLE -- The Guardians got a taste of what a potential Wild Card Series could look like against the Mariners, assuming Cleveland can hang on to the top spot of the American League Central. And the team is escaping Seattle with a handful of things to improve upon before the postseason rolls around.

After two losses to start the four-game set against the Mariners, the Guardians rallied late on Saturday to attempt to split the series. But quiet bats on Sunday afternoon at T-Mobile Park led to a 4-0 loss for Cleveland, dropping its lead in the division to two games.

• Box score

If the playoffs would’ve started the day the Guardians rolled into Seattle on Thursday, the records would’ve dictated that the two clubs go head to head in an AL Wild Card Series.

With an extra Wild Card spot this season, the two division winners with the best records will get a bye in the Wild Card round. The third-best divisional winner (which, for now, is the Guardians) will take on the Wild Card team with the worst record (which, on Thursday, was the Mariners). The two Wild Card teams with the better records will face each other in a separate Wild Card Series.

The Mariners ascended to the No. 2 Wild Card spot, ahead of Toronto, by taking three of four games in Seattle this week. Let’s take a look at three things we learned from the series:

1. Avoid the miscues
This seems like common sense, but the Guardians need to be more sound defensively (and on the bases) than any other team to win. They’ve known this since the start of Spring Training, considering their style of play is much scrappier than most teams in the league. But when they turn just the slightest bit sloppy, it seems like an impossible hurdle to overcome.

The fifth inning on Sunday summed this up perfectly. An error by starter Aaron Civale while attempting to cover first on a potential double-play ball allowed a runner to remain on first with just one out in the frame. He forced the next batter to ground out, but then three runs ensued.

First baseman Owen Miller tried to get the Guardians out of trouble by making a play against the net in foul territory, but he ended up using the net in the process of catching the ball, causing it to just be a foul ball. On the next pitch, Dylan Moore launched a three-run homer.

“Then when it's the next pitch, it hurts a little more than normal,” Guardians manager Terry Francona said.

2. Offensive help
For the most part, the Guardians have been pretty solid offensively. They’ve been able to rely on guys like Steven Kwan, Amed Rosario, José Ramírez, Oscar Gonzalez and Andrés Giménez. When you have that at the top of the order, your confidence in your hitting can only grow. But the bottom of the lineup has become more problematic with Myles Straw leading that pack.

Straw has struggled all season, and his average dipped below the Mendoza line after he went 0-for-2 on Sunday. Since Aug. 1, he has hit a mere .095. No. 21 prospect Will Brennan’s .309 average, 33 doubles, 10 homers and 95 RBIs (including a five-RBI night on Saturday) with Triple-A Columbus has to be enticing, even if he’s not on the 40-man roster.

3. Starting pitching is essential
Cleveland has another AL Wild Card contender to face this week before having to go toe to toe with the Mariners again. And if the Guardians can secure a playoff spot, the pitching they will face will keep getting better. If the bats struggle like they did against reigning Cy Young Award winner Robbie Ray, this team will need to be able to rely on its rotation like it has in recent memory.

Luckily for the Guardians, the starters seem to be heating up at the right time. Over the four-game set, Cleveland pitching gave up just 19 hits in 35 innings. The problem was that six of those 19 hits were home runs.

If the rotation can keep the ball in the park, the Guardians have a chance to suddenly have a really dominant starting staff at the most crucial point in the season.

“Tough series, obviously, here in Seattle,” Civale said. “But that doesn’t change who we are and how we play the game. I think we play the game the right way. Just have to keep doing that.”