Lelo, who earned league most valuable player honors as a sophomore last season, tore the meniscus in her left knee on Dec. 2, and could be done for the season.
But without her, La Cañada (11-4) still entered league play with the area's best record. However, against the Wildcats, who shared the Rio Hondo League title with the Spartans in 2004-05, Tamar Hill's squad sure looked like it could have used No. 10.
The Spartans, who came in shooting 38% from the field on the year, shot a dismal 17 of 56 (30.4%) on Wednesday.
Monrovia (10-4) was actually worse, connecting on just 19 of 66 shots (28.8%), but the Wildcats' backcourt of Krystyn Jacobs and Shannon Gholar combined for 34 points, many of which came on easy drives to the basket.
"We had a lot of open looks, and everyone knows we can make those shots, but we didn't tonight," Hill said.
Without Lelo, who averaged 22.7 points during her first three games before getting injured early in the fourth, the Spartans lacked that go-to offensive player in crunch time.
A key example came during the waning seconds, when La Cañada was down by three points with less than 30 seconds left.
In one possession, the Spartans had three wide-open looks from three-point range, but couldn't connect.
Overall, La Cañada shot seven of 27 from three-point territory.
"We had three great looks but couldn't tie it," Hill said.
Still, the Spartans had one more chance, after Monrovia, which shot 14 of 28 from the free-throw line, failed to make good on the front end of a one and one.
With the final seconds ticking away, La Cañada got the ball to Emily Ballard, who connected from long range, but her toe was on the three-point line.
With 3.2 seconds left, the Spartans were still down by one, and after Monrovia made one of two free throws, all La Cañada could muster was a desperation half-court shot from Ballard.
When her prayer wasn't answered, Monrovia celebrated a key league victory, despite trailing by as many as eight in the first half.
Still, the Spartans know the league championship is far from decided.
"We know we're capable of playing better than we did," said Hill, whose squad was outrebounded, 47-34.
"We didn't execute what we wanted to do."
Monica An was La Cañada's leading scorer off the bench with 12. Jessica Lew added 11 and Mary Kate Hurlbutt and Ballard each finished with 10.
* HAMLET NALBANDYAN covers sports. He can be reached at (818) 637-3226 or by e-mail at email@example.com.