Sunday marked a huge victory for the Mariners, who capped their first four-game sweep of the Astros in franchise history with a come-from-behind, 4-3, victory that kept them firmly in the hunt for both the American League Wild Card and the AL West lead.
But in the bigger picture beyond 2018, Sunday was also important because of Edwin Diaz's insistence on coming in for the save. By locking up his fourth save in as many days, Seattle's closer upped his season total to 46 and he is currently on pace for 63 saves. That would be historic, as Francisco Rodriguez holds the current single-season record with 62 saves for the 2008 Angels.
Diaz has been incredibly dominant in the clutch: He's converted 27 straight saves, recorded 24 saves in one-run games and owns a 0.39 ERA in games that he has saved. Looking forward, the numbers say he'll have to keep his dominance going to potentially break the record. His pace in relation to Rodriguez's can be summed up simply: Neck and neck.

Can Diaz catch -- and ultimately surpass -- K-Rod in the history books? Here are some questions and answers to help set the stage for his stretch-run chase.
Where do Diaz's 46 saves stack up through 119 team games?
In terms of pace through this point of the season, Diaz is exactly on track. Sunday's save helped him tie Rodriguez for the most saves recorded by any pitcher through his team's first 119 contests -- though Diaz has gotten to this point in a more dominant fashion than K-Rod.

It should be noted that batters have struck out in roughly 22 percent of their plate appearances vs. Diaz this season, as opposed to 17.5 percent when Rodriguez made history a decade ago. But Diaz has been more stifling than Rodriguez at this point of the season in just about every measure, including WHIP (0.76 for Diaz, 1.29 for Rodriguez) and opponents' average against (.153 to .197).
How did Rodriguez fare the rest of the way?
Rodriguez walked the tightrope a little more down the stretch, compiling a 1.28 WHIP and allowing a .269 average to opponents over the Angels' final month-and-a-half. But he got the job done when it mattered most. K-Rod converted 16 of his final 18 save opportunities while recording a microscopic 0.50 ERA in his final 20 total appearances, helping the Angels wrap up the American League West title with a 100-62 record. Neither Los Angeles nor Rodriguez needed to sweat much, however, as the Angels cleared the second-place Rangers by an astounding 21 games. Rodriguez broke Bobby Thigpen's previous record of 57 saves on Sept. 13 and then converted four of his final five save chances after that.
How common is it for a reliever to save 60 or more games?
Rodriguez is the only pitcher in MLB history to record 60 or more saves in a season with his 2008 campaign. Only three others recorded 55 or more saves in a single season: Thigpen saved 57 games for the White Sox in 1990, Eric Gagne saved 55 games for the Dodgers in 2003 en route to being named the National League Cy Young Award winner (he also saved 52 in '02), and Hall of Famer John Smoltz saved 55 for the Braves in '02 in his first season as a full-time closer.
Nine others reached the 50-save plateau in a single season: the Yankees' Mariano Rivera (53 in 2004, 50 in '01), the Padres' Trevor Hoffman (53 in 1998), the Cubs' Randy Myers (53 in 1993), Jeurys Familia (51 with Mets in 2016), Mark Melancon (51 with Pirates in 2015), Jim Johnson (51 in 2012, 50 in '13; both with Orioles), the Cubs' Rod Beck (51 in 1998), the Athletics' Dennis Eckersley (51 in 1992) and Craig Kimbrel (50 with Braves in 2013).
Based on Diaz's success thus far, how many save opportunities does he theoretically "need" down the stretch?
Diaz has been nearly lights out to this point, converting 46 of his 49 save opportunities for a 93.9 percent conversion rate. And he's had no shortage of chances; Seattle's propensity for playing tight contests has given Diaz plenty of work -- including four straight games during the Mariners' crucial weekend sweep of the Astros.
Diaz has come on in a save opportunity in 41.2 percent of Seattle's 119 games thus far, and that rate comes out to somewhere between 17-18 more save chances if the Mariners give him a similar amount of work over their last 43 contests. That means Diaz will need to be close to perfect down the stretch, but he already has been just to get himself to this point.
Will the schedule help or hinder Diaz?
Diaz will face a tall order in terms of the Mariners' schedule the rest of the way. Over the final 43 games, Seattle will play 25 against clubs that currently have a record above .500. And the Mariners are slated to play 29 of their remaining games against teams that are currently ranked in the top eight for runs scored this season: Three against the Yankees (ranked second in the Majors in runs scored), six against the division rival Astros (4th), seven against the Rangers (5th), 10 against the red-hot Athletics (7th) and three against the Dodgers (8th).
The grind begins immediately, with 16 of the Mariners' next 18 games against teams above .500. The next three series will be particularly challenging: Three games at Oakland (the Athletics have gone 35-12 since June 16), three against the defending NL champion Dodgers and three versus the defending World Series champion Astros.
What do the projections say?
While FanGraphs' Steamer projections indicate Diaz will tie for baseball's second-most valuable pitcher down the stretch in terms of WAR, the system is not as rosy about his chances at history. Entering Sunday, Steamer had Diaz recording 10 more saves by season's end, which would leave him about a half-dozen saves shy of Rodriguez.
This makes sense because projections always pull a player's statistics back toward the mean, and Diaz has enjoyed an immense amount of opportunities so far. But with Seattle just a game-and-a-half back of Oakland in the Wild Card, and four games back in the AL West, every game will matter down the stretch. Mariners manager Scott Servais is likely to lean on Diaz as much as possible, and Diaz -- if he shows the same mettle that he has to this point -- could carry both himself and the Mariners toward a glorious finish.