The Timbers (4-1-3, 15pts) moved into third place in the USL First Division table with the win, passing Cascadia Cup rival Vancouver.
Portland got its lone goal in the 14th minute when Antoniuk converted his second penalty kick in as many nights, making good on the opportunity after midfielder Scott Benedetti was brought down inside the box.
The Lynx (0-7-4, 4pts) mounted several attempts to equalize in the closing minutes of the match, but the Timbers rebuffed the Toronto attack.
Huffman Eja-Tabe, a late substitution, broke free in the box during stoppage time, but Portland goalkeeper Josh Saunders intercepted the attempt and preserved the win.
Saunders collected his third clean sheet of the season, making four saves while facing eight shots on the night.
Logging his first minutes as a Timber on Saturday, Paul Conway nearly sailed in a left-footed shot from 30 yards out early in the fourth minute, but his attempt ricocheted off the crossbar.
Toronto’s Davis Simpson pulled Saunders off his line in the 41st, but he passed on the shot and the Timbers dodged what was the Lynx’ best scoring chance of the first half.
On tap for the Timbers is a match at Puerto Rico on Monday, June 6. Kickoff is 5 p.m. (Pacific).
TIMBERS NOTES: The Timbers have converted a penalty kick in each of their last three games … three of the team’s last four goals have been on PKs … Portland swept Toronto 2-0 in the regular-season series with the win … the Lynx are the lone team in the league without a win … Timbers fans can log on to www.portlandtimbers.com to check out broadcaster Andy McNamara’s travel blog … McNamara, in his fifth season as the “Voice of the Portland Timbers,” will be updating his web journal on a daily basis.
SCORING SUMMARY: Antoniuk, 14’ (PK).
MISCONDUCT SUMMARY: TOR Munthali, YC (55’).
LINEUPS: PORTLAND (4-1-3) J. Saunders GK, Morrison D, Wilkinson D, Thompson D, Poltl M, Winters M, Lines M, Miranda M, Benedetti M, Antoniuk F (Afash 84’), Conway F (Alvarez 67’); TORONTO (0-7-4) Goddard GK, Henry D, Francois D (Eja-Tabe 67’), Piette D, Titus M, Aristodemo M, Munthali M, Bartolomeu M, Simpson F (Matondo 55’), Fraser F, Dodds F.