Luukkonen returned to the crease Friday, stopping 34 shots before allowing a goal with one second remaining in regulation as LeKi downed RoKi 3-1.
The 6-foot-4 backstop earned his third consecutive start Saturday, stopping 27 shots to improve to a perfect 4-0 on the year in a 5-2 win over Hermes.
In addition to being undefeated, Luukkonen has posted a 1.71 goals-against average and a league-leading .944 save percentage through his first four starts.
Under contract through 2019 with HPK in Finland's top professional league, Luukkonen was placed on a full-season loan to LeKi of the second division so he could play versus a higher level of competition as opposed to serving another season in the under-20 junior league, where he would have been assigned given HPK's current depth at the position.
Casey Mittelstadt (2017, first round) made his NCAA regular season debut Friday, threading a quick, cross-crease feed for an assist as Minnesota lost 4-3 in overtime to Minnesota Duluth at the 2017 IceBreaker.
On Saturday, Mittelstadt connected with a backhand to score his first-ever collegiate goal as Minnesota shut out Union 2-0 in the IceBreaker consolation game.
Despite the opening night defeat, Mittlestadt's first weekend of the regular season was a personal success, with the 18-year-old centerman picking up one goal, one assist, and six shots on goal in his first two games.
On Friday, Boston College defenseman Casey Fitzgerald (2016, third round) notched the primary assist on the game-tying goal with 4:01 left in regulation as Boston College clawed back to a 1-1 overtime tie with Quinnipiac.
Christopher Brown (2014, sixth round) played to an even rating Friday as Boston College opened the season with the 1-1 tie with Quinnipiac.
Jacob Bryson (2017, fourth round) recorded three shots on goal and a plus-2 rating Friday as Providence earned a 3-1 road win at Miami.
Bryson snagged his first points of the season the following night with a pair of helpers as the Friars earned the road sweep with a 3-2 victory at Miami. Bryson's second assist of the night came on a Kasper Björkqvist tally with just 0.9 seconds left on the clock in regulation.
Wisconsin freshman winger Linus Weissbach (2017, seventh round) used his speed to gain the zone and earn a primary assist on the game's first goal Friday as the Badgers fell to Ohio State 3-2.
Weissbach was quieted on Saturday as the Badgers edged the Buckeyes 3-2. Weissbach has two goals and one assist through his first three collegiate tilts.
Third-year defenseman William Borgen (2015, fourth round) recorded an assist as St. Cloud State opened the schedule with a 4-0 shutout of Minnesota State.
Senior forward Judd Peterson (2012, seventh round) also notched an assist for St. Cloud State in the shutout victory of Minnesota State.
Brett Murray (2016, fourth round) logged a minus-1 rating Friday as Penn State was defeated by Clarkson 2-1.
Murray, a 6-foot-5 sophomore, continued plugging fourth-line minutes as the Nittany Lions completed their North Country trip Saturday with a 4-1 win at St. Lawrence.
Connecticut sophomore defenseman Philip Nyberg (2016, fifth round) was hit into the boards late in the first period during Friday's loss at Maine and did not return with a lower-body injury.
Nyberg did not play Saturday as the Huskies earned the weekend split with the Black Bears. The severity of the injury is not yet known.
Massachusetts defenseman Ivan Chukarov (2015, seventh round) suffered an upper-body injury over the summer and is out until at least November.
Senior winger Maxwell Willman (2014, fifth round) remained idle last week as Brown does not begin their season until October 27 versus Yale.
Cliff Pu (2016, third round) registered four shots on goal Friday as London lost to Sault Ste. Marie 4-1, and followed up Saturday with a minus-3 rating as the Knights continued their recent skid with a 5-2 defeat at Erie.
Pu remains goalless with just three assists through his first six games since returning from Buffalo.
In Friday action, defenseman Austin Osmanski (2016, seventh round) logged one shot on goal in Mississauga's 5-4 win over Sudbury.
On Sunday, it was announced that Mississauga traded Osmanski to Peterborough for a pair of fourth round picks. In five games with the Steelheads prior to the trade, Osmanski recorded one assist and eight shots on goal.
Brandon Hagel (2016, sixth round) recorded one assist Saturday as Red Deer was bested by Brandon 5-2.
An assistant captain for the Rebels, Hagel has three goals and eight points in his first six games.
Prince Albert defenseman Vojtech Budik (2016, fifth round) sent three shots on goal Friday as the Raiders came up short 4-1 against Lethbridge, and then finished with a plus-2 rating Saturday in a 6-1 hammering of Medicine Hat.
Six games into the season, Budik has captured a goal and an assist.
After losing a minus-2 rating in Friday's 7-1 loss to Gatineau, Vasily Glotov (2016, seventh round) snapped a five-game funk with his first goal of the year Saturday as Shawinigan lost to Cape Breton 3-2.
Glotov, who finished the week with five shots on goal in a 4-0 shutout loss to Chicoutimi on Sunday, has three points (1+2) in eight contests for the winless Cataractes.
Rasmus Asplund (2016, second round) notched a secondary helper Thursday as Färjestad BK lost in overtime 3-2 to the IF Malmo RedHawks.
On Saturday, Asplund notched one shot on goal and won two of his eight draws as Färjestad cruised past Brynäs 4-1.
Asplund has cemented himself as the Färjestad's second-line centerman, notching three goals and six points in the club's first seven contests.
Elsewhere in Sweden, Victor Olofsson (2014, seventh round) put his sharp-shooting power-play skill on display once again Thursday, beautifully picking a corner for his second goal of the year as Frölunda fell to Lulea 3-2 in overtime.
Olofsson provided two shots on goal Saturday as Frölunda edged Luleå 4-3, leaving the trigger man with three points (2+1) and 11 shots on goal through six games.
Marcus Davidsson (2017, second round) skated for 9:06 as a bottom line centerman Thursday as Djurgarden cruised past Rogle 6-2, and completed the week with a season-high 9:20 of work in a 2-1 win over Vaxjo Lakers HC.
Davidsson has totaled five shots on goal in five games since being recalled from the junior squad.
Defenseman Oskari Laaksonen (2017, third round) had five shot attempts in 22:06 of work Saturday as Ilves U20 blanked Ässät 2-0.
An offensive-minded defenseman, Laaksonen went without a point for the fifth-consecutive game as Ilves dropped a 3-2 overtime decision to the Blues.
Laaksonen has played a leading role in all 14 contests, producing one goals and five points while averaging 24:19 of work per outing.
For more on all the youngsters in the Sabres pipeline, check out Kris Baker's website, SabresProspects.com. You can also follow him on Twitter (@SabresProspects) for in-game updates throughout the week on any Buffalo prospects that are in action.