The Jamaican international didn't disappoint.
Mattocks scored once and set up another as the Whitecaps twice battled back from a goal down to tie the Columbus Crew 2-2 on Wednesday night.
The 24-year-old started 20 times for the Whitecaps last season, but has found himself on the bench for long stretches so far in 2015, playing just 45 minutes through the team's first five games.
"He should be proud of his performance," said Robinson. "He scored a goal. He could have maybe had two or three on a different day."
Octavio Rivero added his MLS-leading fifth goal of the season for Vancouver (4-1-1), which saw its franchise-record four-game winning streak come to an end.
Kei Kamara replied with both goals for the visitors as Columbus (1-2-1) picked up its first road point of the season.
Tied 1-1 at the half, the Crew grabbed the lead in the 50th minute when Justin Meram intercepted a poor clearing attempt by Whitecaps goalkeeper David Ousted. The Columbus midfielder fed a ball from the left into Kamara, who poked home his second of the night and third of the season.
Vancouver responded by bringing on speedy midfielder/forward Kekuta Manneh, and he made his presence felt immediately. After a couple of close calls, the 20-year-old Gambian moved in on goal in the 64th minute, cutting a pass back to Mattocks, who buried his first of the campaign.
"(Manneh) is a great player and every game he plays we know what he's capable of doing and what he's expected to do," said Mattocks. "He just gets by defenders so easily. Fortunately for me I was in the right place at the right time.
"That goal is all owed to him. I told him as soon as I scored 'That's all you, kid.'"
Mattocks — who scored in each of his country's recent friendlies — nearly won it for Vancouver moments later, but his shot smashed against the near post. Columbus goalkeeper Steve Clark then thwarted another attempt from Mattocks as the Whitecaps poured on the pressure looking for an elusive winner.
"Fantastic game. We should have gotten three points," said Mattocks. "Second half, I think the guys did really well to show great character, great (work) ethic. That's what's going to take this club to the next level."
Playing without suspended midfielder Federico Higuain, the Crew opened the scoring in the 24th minute when Kamara jumped on a loose ball in the Vancouver penalty area off a break and beat Ousted.
The Whitecaps, who looked a bit out of sorts early, responded when Mattocks found Rivero with a quick throw into the Columbus penalty area in the 31st. The Uruguayan striker shook off a defender before firing shortside on Clark for his fifth goal in six games since joining Vancouver in the off-season.
"I think we had a enough chances to probably win the game," said Robinson, whose team picked up its MLS-leading 13th point of the season. "We didn't take enough of our chances, but we weren't good enough defensively. We let (in) two sloppy goals. We got countered, and the second goal obviously is a bad goal to concede."
The Whitecaps were playing their second of three games in eight days after Saturday's impressive 2-0 home victory over the Los Angeles Galaxy. There was speculation Robinson might alter his lineup on Wednesday because of the busy schedule, but he elected to make just two changes, with Mattocks and defender Diego Rodriguez — who wound up having to be subbed off after just 15 minutes because of a groin injury — drawing into the starting 11.
"We're disappointed we only got a point," said Robinson. "But that shows how far we've come."
Note: Both the Whitecaps and Crew are back in action on Saturday, with Vancouver visiting the San Jose Earthquakes and Columbus travelling to New England to take on the Revolution.
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