Kwinana totalled a modest score of 152 thanks to tight bowling from Kane Hoskin and Thomas Keefe.
A crafty spell of spin bowling from Kevin Francis (3-11) ripped through the home team’s middle order.
SJ was given yet another flying start thanks to Kane Hoskin (28) and Ryan Makarov (62) and at 1-98 they appeared to be cruising.
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READ NOWNonetheless, eight wickets fell for only 45 runs, with SJ needing a further 10 runs with nine wickets down.
The cool heads of Ian Wood and Thomas Keefe took SJ to a shaky victory and they were finally all out for 170.
Fifth Grade batted first against Hilton-Palmyra at Briggs Park and were in trouble at 4-54 before Liam Davidson (46) and Aaron Ballantyne (47) combined for an 85-run partnership.
SJ finished with 7-176 from their 40 overs.
The visitors were never in the hunt thanks to a fiery eight-over spell from Jarrod Hidding, who knocked the top off the Hilton-Palmyra batting, taking 4-21.
He received good support from Matt Hillyard (1-18) and Phillip Hicks (2-25), and SJ recorded a comfortable 63-run victory.
Teenager James Bakota was the hero for the one day C side as they also recorded a comfortable win in their match against Armadale.
Batting first, SJ rattled up 7-216 from their 40 overs and John Murphy (47) and Sri Srilakshmi (44) top scored.
Armadale was well placed with its score on 4-134 in reply, when Bakota was brought on to bowl.
The young paceman snared all but one of the remaining six wickets, finishing with the impressive figures of 5-30.
Despite a 99-run eighth -wicket partnership between Mark Paterson (77 n.o.) and Jaxon Liddelow (50) the SJ blues 1G side suffered their first loss of the season against Thornlie.
Paterson and Liddelow came together with SJ struggling at 7-77 and their batting allowed SJ to compile a competitive 9-192 from their 35 overs.
Aided by 42 wides, Thornlie was able to pass the target, finishing with 7-207.
Shannon Hill returned the best bowling figures with 2-28 from seven overs, while Shawn Evans was very miserly, conceding only 27 from his seven-over spell.
This Saturday, Second Grade take on Willetton Crows at home, Fifth Grade travel to Cockburn, one day Cs host Phoenix and one day Gs are away to Piara Waters.