Andrew Meredith's Green Machine suffered their second defeat at the Hamburg Masters in Germany as they fell 4-0 to Olympic silver medallists the Netherlands this afternoon.
Ireland, though, did put in an improved performance against Netherlands this afternoon.
In the opening quarter Ireland had the best of possession and scoring opportunities, but the final touch seemingly appeared elusive.
On 15 minutes the Netherlands caught Ireland with a quick counter attack, following a high press leaving Jonker with a 2-v-1 finish to open the score at 1-0.
The game ebbed and flowed thereafter with the scoreline remaining the same until half-time.
Netherlands showed their immediate intent from the start of the second half and took a 2-0 lead on 36 minutes, when Jonkers followed up on a rebound off David Fitzgerald in the Ireland goal from close in.
Van der Weerden made it 3-0 with a penalty corner drag flick in the 45th minute, and Jonker rounded off a 4-0 victory and completed his hat-trick in the 57th minute, when he hit home at the back post from a reverse side-line pass.
With pitch temperatures reaching 40 degrees, this was always going to be a difficult match against a full strength Dutch side.
Ice vests, chilled towels and heads in ice buckets have been the norm for this tournament, which even by Hamburg standards is at the upper end of heat and humidity.
Prior to the match, Mitch Darling was given a presentation by Ireland manager Peter Jackson and the president of the Hamburg Hockey Federation in recognition of his 100th senior international cap.
Ireland starting XI: Fitzgerald, McCandless, Harte, Jackson (Capt), Cargo, Darling, Cole, Shimmins, Sothern, Good, Bell.